Friday

October 21, 2016
Total # Posts: 36,321

**math**

1/3 * -1 1/5 the * symbol is used in this format to stand for multiplication so if you mean (1/3)(-6/5) , then = - 6/15 = -2/5 or -0.4

*October 21, 2016*

**Maths**

6^2 + 2^2 + 3^2 = 49 so the direction cosines are (6/7 , 2/7, 3/7) notice that (6/7)^2 + (2/7)^2 + (3/7)^2 = 1

*October 21, 2016*

**Math**

I agree

*October 21, 2016*

**Math**

Treat the question as if you had two ordered pairs (3,800) and (5,720) slope = (720-800)/(5-3) = - 40 using(3,800) y - 800 = -40(x-3) y = -40x + 920 b) so after 1 year, x = 12 y = -40(12) + 920 = 440 state your conclusion using the proper units

*October 21, 2016*

**Math**

Rent it Cheap = 2900 + 50k Thrift car = 3700+48k solve 2900+50k = 3700+48k and use the result to state your conclusion

*October 20, 2016*

**Algebra**

2𝑦 + 5 = 1/2(4𝑦 + 8) multiply both sides by 2 4y + 10 = 4y + 8 10 = 8, ahhh, I see your problem, the y's dropped out ok, if your variables drop out, and you end up with a false statement, such as our 10=8, then the equation has no solution. If we end up ...

*October 20, 2016*

**Math**

"2n up3" ?? did you mean 2n^3 ? or perhaps (2n)^3 ? clarify please.

*October 20, 2016*

**Math**

let the middle number be x then x/5 = 245/x x^2 = 1225 x = ± 35

*October 20, 2016*

**Math**

940 = 20 x 47 ---> 47 is prime 420 = 20 x 21 The GCF = 20

*October 20, 2016*

**maths**

c) ii) you asked how many study French, but your first data information says that 9 study French Either you meant 9 to be "French only" , or else the question is bogus. Confirm.

*October 20, 2016*

**Algebra**

area of the 4 windows = 4(30/12)(48/12) = 40 ft^2 area of floor = 10(40) = 400 ft^2 (where does the ridiculous height of 50 ft come in ?) ratio of window area : floor area = 40:400 = 1:10

*October 20, 2016*

**Math**

1st derivative: -sinx 2nd derivative: -cosx 3rd derivative: sinx 4th derivative: cosx 5th derivative: -sinx .. 14th derivative: etc. notice we are in a cyclical loop of 4 results, notice 999 leaves a remainder of 3 when divided by 4, so the result is the same as the 3rd ...

*October 20, 2016*

**Math help please!**

done, look at Dan's problem below. Are you switching names?

*October 18, 2016*

**Math Please help**

let the number of units be x return = 9x cost = .4(9x) + 50000 at "break-even" point, they are equal 9x = 3.6x + 50000 5.4x = 50000 x = 9259 carry on

*October 18, 2016*

**Algebra**

Neither one has an average elevation of -2 Average elevation of Long Beach = (360 + (-7) )/2 = 176.5 units You do the other one in the same way to show the question is bogus

*October 18, 2016*

**Science, Math**

Your choices make no sense to me

*October 18, 2016*

**Science Earth**

If 10 million years ----> 1 cm 4.6 billion/(10million) = 4.6 x 10^9/(10 x 10^6) = 460 You will need 460 cm or 4.6 metres

*October 18, 2016*

**Maths**

346° + 30° = 376° = 360° + 16° = 1 rotation + 16°<----- same as a direction of 16°

*October 18, 2016*

**Geometric progression**

apparently three numbers are in a GP then the 3 numbers are: a, ar, and ar^2 "the continued product of three numbes in g.p. is 216" I am guessing you mean: a(ar)(ar^2) = 216 a^3 r^3 = 216 ar = 6 a = 6/r "the sum of their products in pair is 156" a(ar) + a(...

*October 18, 2016*

**Geometric progression**

Let the original numbers be a, a+d, and a+2d 3a + 3d = 15 or a+d = 5 ----> d = 5-a after the addition, the three numbers are: a+1, a+d+4, and a+2d+19 they are now in GP, that is .... (a+d+4)/(a+1) = (a+2d+19)/(a+d+4) (a + 5-a + 4)/(a+1) = (a + 10-2a + 19)/(a + 5-a + 4) 9/(a...

*October 18, 2016*

**Algebra2**

following up on John's observation, let y = k/x for (5,2) 2 = k/5 k = 10 y = 10/x check for (10,1) is 1 = 10/10, yes check for the last one: (20, 1/2) is 1/2 = 10/20 , yes

*October 17, 2016*

**Math**

If 3/8 of the 240 students are boys, then 5/8 will be girls or 15 will be girls. 3/5 of the girls have short, so I will assume that 2/5 will have long hair, assuming none of the girls are bald (2/5)(15) = 6 6 of them have long hair

*October 17, 2016*

**Math**

because I can write is a fraction .57 = 57/100

*October 17, 2016*

**Math (Confused)**

Not confusing at all, simply replace wherever you see an x with the given value, C(x) = .75x + 5 C(0) = .75(0) + 5 = 5 that rules out a), b), and e) C(50) = .75(50) + 5 = 42.5 so far, only c) works simply check by finding C(100)

*October 17, 2016*

**Ratio**

Just like in your previous question , I looked up "duplicate ratio" http://www.math-only-math.com/types-of-ratios.html and again, just follow the definition ( Where and in what course are they teaching this?)

*October 17, 2016*

**Ratio**

I actually had to look this up, had never heard of it. Subduplicate ratio: The sub duplicate ratio m : n is the ratio √m : √n. So, the sub duplicate ratio of the ratio m22 : n22 is the ratio m : n. For example: The sub duplicate ratio of 25 : 81 = √25 : &#...

*October 17, 2016*

**Math115**

done, check back to your last post of this

*October 17, 2016*

**Differentiation**

use x^2 to show "x squared" etc I would expand it first, just like in my previous reply , then take the derivative. check your answer by doing it both ways, like I showed you

*October 17, 2016*

**Differentiation**

did you mean y = (x^2 - 5x+6)(x-3) ? For this one, I would have actually expanded it. y = x^3 - 3x^2 - 5x^2 + 15x + 6x - 18 = x^3 - 8x^2 + 21x - 18 dy/dx = 3x^2 - 16x + 21 or .... by the product rule: dy/dx = (x^2 - 5x + 6)(1) + (2x - 5)(x-3) = x^2 - 5x + 6 + 2x^2 - 6x - 5x + ...

*October 17, 2016*

**Arithemetic progression**

use your formula a = 5, d = 2 , n = ? , sum(n) = 480 (n/2)(10 + 2(n-1)) = 480 n(8 + 2n) = 960 8n + 2n^2 = 960 n^2 + 4n - 480 = 0 (n+24)(n-20) = 0 n = -24 or n = 20 , but n must be a whole number the sum of 20 terms would be 480 check: sum(20) = (20/2)(10 + 2(19)) = 480

*October 17, 2016*

**correction - Arithmetic progression**

First of all we need all the even number, which are 2,4,6,..., 98 there are 49 of them, so sum(49 evens) = (49/2)(4 + 2(48)) = 2450 Now this includes all multiples of 5 that end it 0, but not those that end in 5 so we have to add 5,15,25,35,45,55,65,75,85, and 95 they add up ...

*October 17, 2016*

**Math115**

looks like you considered 1968 as t = 0 , that's fine so you would two ordered pairs (0,20000) and (25,100000) I agree with your linear equation, but you should state it as p(t) = 20000 + 3200t, where t is the number of years after 1968 for the exponential: let p(t) = ...

*October 17, 2016*

**Maths**

let the amount be x x(1.06)^2 - x(1 + 2(.06)) = 92 x(1.1236) - x(1.12) = 92 .0036x = 92 x =25,555.56

*October 17, 2016*

**algebra**

Danielle's age ---- x Travis' age ------ x+19 14 years from now: Danielle ------- x + 14 Travis ---------- x+19 + 14 = x+33 x+33 = 2(x+14) take over, it is easy from there.

*October 16, 2016*

**6th grade algebra**

What does the weight of the flag have to do with the width of the stripes?

*October 16, 2016*

**Math**

starting amount ---- x spent $5, amount left = x-5 after spending half of that on jogging shoes, amount left = (1/)(x-5) after spending $2 for lunch, amount left = (1/2)(x-5) - 2 spent half of that on a DVD, amount left = (1/2)[(1/2)(x-5) - 2] which equals 10 (1/2)(x-5) - 2 = ...

*October 16, 2016*

**Math**

I am going to rephrase your question, without fancy symbols cos(7E) + cos(3E) = cos(5E) , where 0 ≤ E ≤ 360° Correction on the formula you are using: should say: cosA + cosB = 2cos((A+B)/2)cos((A-B)/2) so cos(7E) + cos(3E) = 2cos(5E)cos(2E) but cos(7E) + cos(2E...

*October 16, 2016*

**Maths**

I will assume your "using while numbers" should say "using whole numbers" so 36 = 1 x 36 = 2 x 18 = 3 x 12 = 4 x 9 = 6 x 6

*October 16, 2016*

**value**

x^2 - 13x = 30 x^2 - 13x - 30 = 0 (x-15)(x+2) = 0 can you take over ?

*October 16, 2016*

**math trig**

Find an old mathbook with trig tables, go to the sine column, find the nearest value of the angle so that sinØ = .6 The nearest angle you will find is 37°

*October 16, 2016*

**Calculus**

a) let y = f(x) * g(x) then y' = f(x)* g '(x) + g(x) * f '(x) given: f(4) = 3 f '(4) = -2 g(4) = 6 g '(4) = -4 so y' = 3(-4) + 6(-2) = -24 how did you get -27 ? do the others the same way

*October 15, 2016*

**Calculus**

Treat it as two ordered pairs, (11,27000) and (10,34000) and then find the equation of the line like you did in grade 9 slope = (34000-27000)/(10-11) = -7000 y = mx + b y = -7000x + b using (10,34000) 34000 = 10(-7000) + b b = 104000 y = -7000x + 104000 , y ≤68000 so at ...

*October 15, 2016*

**Math**

Make a sketch. Draw a radius to the base of the isosceles triangle. let the base of the isosceles triangle be 2x, and let its height be h+12 area = (1/2)(2x)(h+12) = x(h+12) but x^2 + h^2 = 12^2 x^2 = 144 - h^2 x = (144 - h^2)^(1/2) area = (144 - h^2)^(1/2)(h+12) d(area)/dt...

*October 15, 2016*

**Mathematics**

unit digit ---- x tens digit --- y so the number is 10y + x 10y + x - 18 = 10x + y 9y - 9x = 18 y - x = 2 also: x+y=6 add those last two equation: 2y = 8 y = 4 so x = 2 the number is 42 check: is 42 - 18 = 24 ? YES

*October 15, 2016*

**math**

n/18m = (2^2x3^2x7)m/18 = 2x7m = 14m since m is a natural number, 14m is always a whole number. did you mean: n/(18m) ? make the necessary changes.

*October 15, 2016*

**Scince**

"A person is standing on 60m height per hour" - makes no sense to me

*October 15, 2016*

**Trigonometry**

I am sure you meant: (1+tan 200° tan 80°)/ (tan200°-tan 80°) --- those brackets are critical recall: tan(A-B) = (tanA - TanB)/( 1 + tanAtanB) = 1/[ (1+tanAtanB)/(tanA - tanB) ] tan(200-80) = tan 120 = - tan60° = -√3 = (tan 200 - tan80)/(1 + ...

*October 15, 2016*

**math**

number of ways without restriction: 9!/9 = 8! now let's put Sam between Ron and Ed RSE or ESR, so that's 2 ways let's consider RSE as one grouping, that means we still have 6 others to arrange number of ways = 2x7!/7 number of ways for the stated condition = 8! - 2...

*October 15, 2016*

**Pre-calculus**

Did you notice 16+29 = 45 ? so sin16° cos29° + cos16° sin29° = sin(16+29) = sin 45 = 1/√2 or √2/2

*October 15, 2016*

**math (Reiny please help)**

As Steve already pointed out to you, the question is not clearly stated. http://www.jiskha.com/display.cgi?id=1476444898 How many songs are on the album? The way you stated it , we could have 3 R, 4 C, and 1 H as an album, or 1R, 1H, or ... What about the order of the songs? ...

*October 15, 2016*

**Pre-calculus**

Steve's answer of 45° is correct, I didn't see the "acute" angle part, and 180-135 = 45°

*October 15, 2016*

**Pre-calculus**

You should know that the slope of a line is the same as the tangent of the angle that the line makes with the x-axis 2x-3y-6=0 , slope = 2/3, tanØ = 2/3, Ø = appr 33.69° with the x-axis same with x+5y-20=0 slope = -1/5 , line leans to the left. angle with x-...

*October 15, 2016*

**Pre-calculus**

sin(α+β+γ) , I will use sin(a+b+c) for easier typing = sin( (a+b) +c) = sin(a+b)cos c + cos(a+b)sin c = (sinacosb + cosasinb)(cosc) + (cosacosb - sinasinb)sinc = sinacosbcosc + cosacoscsinb + cosacosbsinc - sinasinbsinc now put back your α,β, and γ

*October 15, 2016*

**math (Reiny please help)**

No. You are simply choosing 4 of 15 things, and since the order of placing the order does not change, it is simply C(15,4) to order the pizza. Now for the size, you will choose 1 of the 5 sizes or C(5,1) = 5 so number of ways = C(15,4) x C(5,1) = (1365)(5) = 6825

*October 15, 2016*

**maths**

clean up your equations x/4 + y/5 = 1 --times 20 --> 5x + 4y = 20 2x/9 - y/9 = -2 -----> 2x - y = -18 y = 2x+18 using substitution, 5x + 4(2x+18) = 20 carry on

*October 15, 2016*

**Pre-calculus**

sin x=-3/5 and sec x>0 ---> sin x=-3/5 and cos x>0 so your angle must be in quadrants IV If you sketch your triangle , you will realize that you are dealing with the 3-4-5 right-angled triangle, and using the CAST rule sinx = -3/5 , cscx = -5/3 cosx = 4/5, secx = 5/4 ...

*October 15, 2016*

**Differentiation**

According to your suggested answer, I think your function was y = 2^x then taking the ln of both sides: lny = ln(2^x) = x ln2 now differentiate, y' / y = ln2 y' = y(ln 2) = ln2 (2^x) you cannot use log2 , it must be ln2

*October 15, 2016*

**Arithmetic progression**

let the four parts be a, a+d, a+2d, and a+3d a + a+d + a+2d + a+3d= 24 4a + 6d = 24 2a + 3d = 12 ----> d = (12-2a)/3 a^2 + (a+d)^2 + (a+2d)^2 + (a+3d)^2 = 164 4a^2 + 12ad + 14d^2 = 164 2a^2 + 6ad + 7d^2 = 82 2a^2 + 6a(12-2a)/3 + 7(12-2a)^2/9 = 82 times 9 18a^2 + 216a - 36a^...

*October 15, 2016*

**Math**

The area of the lawn is 15 m^2 The path has no effect on the area of the lawn

*October 15, 2016*

**Geometric progression**

You posted over 20 of these type of questions yesterday. Did you even look at some of the replies? Are you attempting to learn how to do these kind of problems? Show me how you started this one, and I will try to guide you along.

*October 14, 2016*

**Algebra**

current ages: billy ---- x Suzy --- x+10 next year: billy --- x+1 Suzy --- x+11 x+11 = 2(x+1) carry on

*October 13, 2016*

**Math (Reiny please help!)**

you are welcome

*October 13, 2016*

**Math (Reiny please help!)**

The actual steps will vary from person to person, and there is no single way to solve this. You sort of have to decide on the simplest equation as a starting point. In this case it is the last equation, it only has two variables. 2x + 2z = 4 , or x + z = 2 ---> x = 2-z I ...

*October 13, 2016*

**Algebra. NEED HELP ASAP PLEASE**

the way you typed it ... 4(t − 1) + 4/4t + 4 = 4t - 4 + 1/t + 4 = 4t + 1/t Something tells me you meant: 4/(t-1) + 4/(4t+4) = 4/(t-1) + 1/(t+1) , the LCD is (t-1)(t+1) = ( 4(t+1) + t-1)/((t-1)(t+1)) = (4t + 4 + t - 1)/(t^2 - 1) = (5t + 3)/(t^2 - 1) , t ≠ ± 1

*October 13, 2016*

**Algebra**

Follow the same steps as in the post when you were Lay.

*October 13, 2016*

**Algebra**

y = 2(x+5)(x-1) http://www.wolframalpha.com/input/?i=plot+y+%3D+2(x%2B5)(x-1)

*October 13, 2016*

**Algebra**

obvious first equation: x + y = 40 2nd equation deals with value of the nuts 6x + 4y = 4.75(40) 6x + 4y = 190 3x + 2y = 95 ** double the first one: 2x + 2y = 80 *** subtract *** from ** x = 15 in your head looking at x+y = 40 y = 25 check: 6(15) + 4(25) = 190 4.75(40) = 190

*October 13, 2016*

**algebra**

correct, now solve the equation

*October 13, 2016*

**Math**

For each of them , make a sketch In each case you will get a right-angled triangle You MUST know the basic trig ratios in terms of opposite, adjacent, and hypotenuse. e.g. tanØ = opposite/adjacent 1) so we have tanØ = 160/120 = 4/3 Make sure your calculator is ...

*October 13, 2016*

**math**

wx + zy = c zy = c - wx y = (c - wx)/z

*October 13, 2016*

**Math HELP!**

looks like for every increase of 1 in the x, the y decreases by 5 so the slope = change in y/change in x = -5 notice (0,-1) is the y-intercept, so y = -5x - 1

*October 13, 2016*

**Investment**

i = .04/4 = .01 n = 12 What is the question?

*October 13, 2016*

**math**

(7^-64)x(7^-150)/(7^-7)x(7^2)=7^t when multiplying powers with the same base, keep the base and add the exponents Left Side = 7^(-64 -150 -7 + 2) = 7^-209 so we have: 7^-209 = t^t clearly t = -209 If the text has an answer of +209, it is wrong. Do you perhaps have a typo, such...

*October 13, 2016*

**math**

a)no restrictions (my answer is 11C5) -- correct b)all boys (is this correct 5C5) -- correct c)all girls (my answer 6C5) -- correct d)more girls than boys (answer 6C4x5C1 +6C3x5C2)? ---- more girls than boys ---> 3G,2B - 4G,1B - 5G = C(6,3)xC(5,2) + C(6,4)xC(5,1) + C(6,5) e...

*October 13, 2016*

**math**

easier to see the letters this way: B I I I O E E E N N N G G R number of ways without restrictions = 14!/(3!3!3!2!) = 201,801,600 (do you know why I am dividing by 3!3!3!2! ? ) let's put the BO together, could also be OB let's treat that pair as one element number of ...

*October 13, 2016*

**math**

Perhaps you feel more comfortable with rectangular graphing r=2/1+cos theta r = 2/(1+ x/r) r + x = 2 √(x^2 + y^2) + x = 2 √(x^2 + y^2) = 2-x square both sides x^2 + y^2 = 4 - 4x + x^2 y^2 = 4 - 4x Steve meant to say, vertex is (1,0)

*October 13, 2016*

**algebra**

speed of slower car --- x mph speed of faster car ---- x+7 mph distance of slower car = 3x distance of faster car = 3(x+7) 3x + 3(x+7) = 273 carry on ...

*October 12, 2016*

**problem solving**

mike's age ---- x years Sandra's age --- x-8 years Six years ago: Mike was x - 6 Sandra was x-8-6 = x-14 x-6 = 3(x-14) x-6 = 3x - 42 36 = 2x x = 18 Mike is now 18 and Sandra is now 10 years old check: 6 years ago Mike was 12 and Sandra was 4 which is 3 times as old My ...

*October 12, 2016*

**math**

2^-3=1/x 2^3 = x x = 8, you are correct 7^y=1/49 7^y = 1/7^2 t^y = 7^-2, thus y = -2

*October 12, 2016*

**7th Math**

First of all , if you have a "hypotenuse", then you must have a right-angled triangle. If the sides are 10 cm each, then the area of one triangle = (1/2)(10)(10) = 50 cm^2 Assuming you have 16 of those, then the total area is 800 cm^2 btw, the hypotenuse would be &#...

*October 12, 2016*

**Quick math help**

Find the tenth term of the sequence: -6,1,8... Is it 57? YES For the sequence:2,4,8,16 the value of s4 is____. Is it 8? If s4 means the sum of four terms, why not just add them up, they are there in front of you, sum(4) = 30 Find the 7th term of the sequence: 1,2,4,... Is it ...

*October 12, 2016*

**Quick math help**

1. list the terms a(n) = 4n, start with n=1,2,.. terms are 4, 8,12, 16, 32 now add them up 2. I think you mean a(n+1) = 4a(n) + 18, where a(1) = 3 a(2) = 4a(1) + 18 = 4(3)+18 = 30 a(3) = 4a(2) + 18 = 4(30)+18 = 138 carry on to a(6) This is called a recursive sequence, where ...

*October 12, 2016*

**geometry**

why are you reposting this? Steve already did it for you http://www.jiskha.com/display.cgi?id=1476313817

*October 12, 2016*

**geometry**

Is there a question?

*October 12, 2016*

**maths**

confusing wording. I interpret that to say, d = -3 sum(15) = -120 sum(15) = (15/2)(2a + 14(-3) ) = -120 15( 2a - 42) = -240 2a - 42 = -16 2a = 26 a = 13 first term is 13 last term = term(15) = a+14d = 13 + 14(-3) = -29 check: sum(15) = (15/2)(first + last) = (15/2)(13 -29) = -120

*October 12, 2016*

**Geometry**

let the other endpoint be (x,y) I will find the x, then you find the y using the same method. for the x: (x+3)/2 = 5 x+3 = 10 x = 7 for the y: ......

*October 12, 2016*

**math**

speed of lorry ---- x km/h speed of car ----- x+20 km/h time for the car = 280/(x+20) time for lorry = 280/x 280/x - 280/(x+20) = 70/60 divide by 70 4/x - 4/(x+20) = 1/60 times 60x(x+20), the LCD 240(x+20) - 240x = x(x+20) 240x + 4800 - 240x = x^2 + 20x x^2 + 20x - 4800 = 0 (x...

*October 12, 2016*

**Maths**

so there are 15 boys and 16 girls prob(that both picked are girls) = C(16,2) / C(31,2) = 120/465 = 8/31 or prob(girl, girl) = (16/31)(15/30) = (16/31)(1/2) = 8/31

*October 12, 2016*

**Math**

I am sure that the work to be shown should look something like this: 17/2 = x/5 2x = 5(17) x = 85/2 or 42.5 2. 22/30 = 100/x 22x = 3000 x = 3000/22 or 1500/11 or 136 4/11 3. you said: 2/1 = 12/2 or 2 = 6 !!!! , surely that made no sense to you.

*October 12, 2016*

**Math Check Answers**

1. 1 7/8 + 1/9 = 15/8 + 1/9 , LCD = 72 = 135/72 + 8/72 = 143/72 none of the choices match 2. 8 8/9 - 5 1/11 = 80/9 + 56/11 = 880/99 + 448/99 = 1328/99 none of your choices match this. 3.3.) 7 2/3 x 3 7/9 = 23/3 x 34/9 = 782/27 not your choice. are you just guessing? show me ...

*October 12, 2016*

**geometry**

basic trig ratios .... cos60° = yz/12 yz = 12 cos 60° = ..

*October 12, 2016*

**maths**

I let a = 20° and tested your equation the way you typed it, it is not true did you mean: [(x+y)/(x-y)]^(2x)+y/2]^2=1 ? or [( (x+y)/(x-y)]^2 )x)+y/2]^2=1 ? or ....

*October 12, 2016*

**math**

make your sketch. let AB = BC = y let AC = x so 2y + x = 82 x = 82-2y given the information, that is as far as we can go

*October 12, 2016*

**math**

2(x-4) ≤ 17

*October 12, 2016*

**Plane and solid geometry**

you will have to "complete the square" 2x^2+4y^2-12x-64y-16=0 2(x^2 - 6x + ....) + 4(y^2 - 16y + ....) = 16 2(x^2 - 6x + 9) + 4(y^2 - 16y + 64) = 16 + 2(9) + 4(64) 2(x-3)^2 + 4(y-8)^2 = 290 divide each term by 290 2(x-3)^2 /290 + 4(y-8)^2 / 290 = 1 (x-3)^2 / 145 + (y...

*October 12, 2016*

**Math for Reiny**

you are correct at -1 I made an error, (shouldn't do stuff in my head) I think I was taking csc^2 (45°) , π/2 = 90°, not 45° my bad

*October 12, 2016*

**Math**

y = -1/(x+5) - 1 step #1 in finding the inverse is to interchange the variables, so x = -1/(y+5) - 1 now solve this for y x+1 = -1/(y+5) (x+1)(y+5) = -1 xy + 5x + y + 5 = -1 y(x+1) = -5x - 6 y = -(5x+6)/(x+1), x ≠ -1,-5

*October 12, 2016*

**Math**

Perfect setup, notice the coefficients of x are ±2, so nothing has to be done add 2nd and last ---> 2y + 4z = 2 , #4 add 1st and last ---> 5y + 6z = 5 , #5 #4 times 5 ----->10y + 8z = 10 #5 times 2 ----> 10y + 12z = 10 subtract those two equations: 4z = 0 z...

*October 12, 2016*

**math**

You couldn't have two different answers. There are 12 white or green marbles so prob(a white or green) = 12/ 17

*October 12, 2016*

**math**

Since you are drawing ONE marble, the prob( white AND green) = 0 That should have been obvious, how can you have a white and a green marble at the same time. My question to you... What is the probability if drawing a white OR a green ?

*October 12, 2016*