Sunday

May 29, 2016
Total # Posts: 34,824

**Algebra 1**

hint: if there are x cans and you have 800 cans and bottles, wouldn't the number of bottles be 800-x ?
*April 8, 2016*

**algebra**

As Bob noted you don't have an equation. you probably have the expression (x - 1/x)/(1 + 1/x) and are asked to simplify it. Hint: how about multiplying the fraction by x/x
*April 8, 2016*

**math**

Why would "guess" for math problems Surely you could have tried to work them out #6 is trivial #8-12 deal with the rules of multiplying and dividing powers When multiplying powers with the same base, keep the base and add the exponents e.g. x^4 * x^8 = x^12 When ...
*April 8, 2016*

**math {sequences}please help**

#3 is geometric with a common ratio of 1/3 your other answers are correct
*April 8, 2016*

**GEOMETRIC SEQUENCES**

No Think of how you would obtain the next term you could take .18 of the previous term and subtract or just take .82 of it so the sequence is: 20000 , 20000(.82), 20000(.82)^2 , .... so r = .82 I am sure you can now answer the question
*April 8, 2016*

**math**

No interest ? Give it to me and after 35 years, my estate will pay you back 1000(12)(35) or $ 420,000
*April 8, 2016*

**math**

let the tens digit be x then the unit digit is 3x so the number is 10x + 3x = 13x the number reversed is 10(3x) + x = 31x 31x + 13x = 88 44x = 88 x = 2 3x = 6 The original number was 26 check: is 26 + 62 = 88 ? YES my answer is correct
*April 8, 2016*

**linear equation in one variables**

let unit digit be x then tens digit is 9-x the number is : 10(9-x) + x = 90 - 9x the number reversed is 10x + 9-x = 9x + 9 9x+9 - (90-9x) = 27 18x - 81 = 27 18x = 108 x = 6 unit digit is 6 tens digit is 3 The number is 36
*April 8, 2016*

**elementary quantitative methos**

This is just finding the P of a PV. Same formula, same story.
*April 8, 2016*

**elementary quantitative methos**

beginning of 2nd year ---> end of first year. I will assume the 12th payment has been made outstanding balance = 230000(1.01625)^12 - 3817.23( 1.01625^12 - 1)/.01625 = ....
*April 8, 2016*

**elementary quantitative methos**

subtract 100,000 from 240,000, that is your PV i = .195/12 = n = 240 P = ? straight formula application ( I got 3817.23 )
*April 8, 2016*

**elementary quantitative methos**

Use the PV formula I showed you in your previous post
*April 8, 2016*

**elementary quantitative methos**

i = .085/4 = .02125 n = 20 amount = A = 30000 payment = P = ? You must memorize the formulas A = P( (1+i)^n - 1)/i and PV = P (1 - (1+i)^-n )/i, where PV is the present value just sub in all your data and solve for the missing variable. 30000 = P( 1.02125^20 - 1).02125 30000...
*April 8, 2016*

**Math**

number of stickers ---- x number of ballons --- 6x bubbles ----- (1/3)(6x) = 2x x + 6x + 2x = 135 solve for x
*April 7, 2016*

**Math**

I assume you mean by just guessing. he must get 8 right, or 9 right or 10 right = C(10,8)(1/2)^8 (1/2)^2 + C(10,9)(1/2)^9(1/2) + C(10,10) (1/2)^10 = (1/2)^10 ( 45 + 9 + 1) = 55(1/2)^10 = 55/1024 not good, better study
*April 7, 2016*

**Math**

let the side of square ABCD be x then area = x^2 area of square EFGH = 2x^2 side of square EFGH = √2 x EF = √2 x AC^2 = x^2 + x^2 = 2x^2 AC = √2 x AB/AC = x/√2x = 1/√2 AB/EF = x/√2x = 1/√2 thus AB/AC = AB/EF
*April 7, 2016*

**Math**

original price ----- x dollars .85(1.08)x = 688.50 solve for x
*April 7, 2016*

**Math**

In a refection over the x-axis, the x coordinate would stay the same, but the y would turn into its opposite that is, (x,y) ---> (x, -y) A(2,-5) ---> A'(2,5) find the choice that matches this
*April 7, 2016*

**pre ap math**

If it is lauched from a height of 48 ft, then the equation should be h = -16t^2+32t+48 I will assume a typo you want h = 0 (at ground level h=0) 0 = -16t^2+32t+48 t^2-2t-3 = 0 It factors, (t-3)(t+1) = 0 t = 3 or t = -1, rejecting the negative time it took 3 seconds
*April 7, 2016*

**linear equations in one variable**

Let the number of ₹5 coins be x then the number of ₹2 = 3x and the number of ₹1 = 160 - x - 3x = 160 - 4x Now for the value: 5x + 2(3x) + 1(160 - 4x) = 300 5x + 6x + 160 - 4x = 300 7x = 140 x = 20 You have 20 ₹5 coins 60 of the ₹2 coins and 80 of ...
*April 7, 2016*

**math probability**

The prob that you get a 7 when rolling two dice = 1/6 so when two friends roll , (the same result as you rolling twice) prob(2 7's ) = (1/6)(1/6) = 1/36
*April 7, 2016*

**math**

area of trap = (1/2)(sum of parallel sides)(distance between them) (1/2(a + 12)(6) , where a is the other parallel side. (1/2(a + 12)(6) = 48 3(a+12) = 48 3a + 36 = 48 3a = 12 a = 4
*April 7, 2016*

**math**

Am I looking at 3 equations? separate them with commas. what is 3y+x-×=10-x ? is x-× a power like x^-x ??
*April 7, 2016*

**Precal**

Don't you have a calculator? make sure you catch the double negative in the last term since cos 135 is negative
*April 7, 2016*

**Math-soh cah toa**

make a sketch. label the ends of the bridge A and B make angle A = 41° and angle B = 48°. label the point on the river P and Q on AB so that PQ is at right angles to AB. Let PQ = h let QB = x , the AQ = 140-x tan41 = h/(140-x) h = (140-x)tan41 tan48 = h/x h = xtan48 So...
*April 7, 2016*

**Math**

I will do one of the components, you do the other , then subtract them a(x) = 3x - 7 and b(x) = 2 - x^3 a(b(3)) = a(2-3^3) = a(-25) = 3(25) - 7 = 68
*April 7, 2016*

**Math**

just follow the definition: f(a,b) = 2a - 3b^2 + 7 f(b,3) = 2b - 3(3)^2 + 7 = 90 2b - 27 + 7 = 90 2b = 110 b = 55
*April 7, 2016*

**Math**

y = 5x-12 inverse: x = 5y-12 5y = 12-x y = (12-x)/5 f^-1 (x) = (12-x)/5 f(x+1) = 5(x+1) - 12 = 5x - 7 5x-7 = (12-x)/5 25x - 35 = 12 - x 26x = 47 x = 47/26 check my arithmetic
*April 7, 2016*

**Math**

We are told : a#b=ab-a-b+1 so x#7 = 7x - x - 7 +1 = 42 6x = 48 x = 8
*April 7, 2016*

**Math**

x^2 + 12x = 73 let's complete the square, the easiest way to solve this particular one x^2 + 12x + 36 = 73+36 (x + 6)^2 = 109 x + 6 = ± √109 x = -6 ± √109 the positive one looks like √109 - 6 so a = 1, b = -6 a+b = -5
*April 7, 2016*

**Math**

What part of my solution I gave you here did you not like ? http://www.jiskha.com/display.cgi?id=1459995714
*April 7, 2016*

**Geometry**

did you notice that you are given two angles in each of the triangles ? Did you notice that their sum is 180 degrees? So they are similar, thus the corresponding sides are proportional. What are we supposed to find ?
*April 7, 2016*

**Algebra II**

Show Thomas a simplified example of why his idea is wrong 3^2 + 4^2 = 5^2 ---- true then 3 + 4 = 5 ????? If you want to take the square root, you have to take it of the whole side, not the individual terms
*April 7, 2016*

**Calculus**

f'(-4) = 9 f'(0) = 6 f'(x) = 3ax^2 + 2cx f'(-4) = 48a - 8c = 9 f'(0) = 0 + 0 = 6 Oh, oh, something fishy here. Check your typing or check the question
*April 7, 2016*

**Calculus**

f(x) is increasing if f'(x) is positive so (x−8)^7(x−1)^4(x+19)^8 > 0 we know that (x−1)^4(x+19)^8 is always positive since we have even exponents. So all we have to do is look at (x-8)^7 > 0 if x > 8 then (x-8)^7 > 0 if x < 8 it is ...
*April 7, 2016*

**Calculus**

f(x) = √(36-x^2) = (36-x^2)^(1/2) f ' (x) = (1/2)(36-x^2)^(-1/2) (-2x) = 0 for a max/min thus x = 0 , f(0) = 6 but f(1) = √(36-1) = √35 which is < 6 f(6) = √0 = 0 So the absolute minimum is 0
*April 7, 2016*

**math**

in a), b), and d) the first points don't work leaving c) in c) the 2nd point does not work so none of triples have all 3 correct
*April 7, 2016*

**math**

the way you typed according to BEDMAS (1/15)(6+x)=(1/6)(x+3) multiply both sides by 30 2(6+x) = 5(x+3) now it is easy, carry on What Bob meant was: did you mean, 1/(15(6+x)) =1/(6(x+3)) ? then we have an entirely different ballgame
*April 7, 2016*

**math**

All of them are NOT a solution
*April 7, 2016*

**check this - maths**

I must have made some kind of error in this big mess. I can't reconcile the fact that k = 6 will produce the 45 degree angle, but both of our solutions somehow showed that k = 2 I will look at it again later on today
*April 7, 2016*

**maths**

x^2 + xy - Ky^2=0 To have this equation represented by two straight lines, we must have it in a factored form such as (x + ay)(x - by) = 0 so that a+b = 1 and ab=-k e.g. if we had x^2 + xy - 6y^2 = 0 (x+3y)(x-2y) = 0 our two lines would be x+3y = 0 or x-2y = 0 slope of first...
*April 7, 2016*

**Algebra**

Winner of the most nonsensical question of the day.
*April 6, 2016*

**Math**

amount = 1500 + 1500(1.05^4 - 1)/.05 = 7965.19
*April 6, 2016*

**Math**

x^2 - 5x - 4 < 10 x^2 - 5x - 14 < 0 (x-2)(x+7) < 0 if y = (x-2)(x+7) we have a parabola opening upwards with x-intercepts of 2 and -7 the parabola would be below the x-axis, that is y < 0 , for -7 < x < 2
*April 6, 2016*

**Math**

the maximum area is obtained when your rectangle is a square. so let the side be s 4s = 24 s = 6 area = 36
*April 6, 2016*

**Math**

again, just like in your last post, just do it m/n@p/q = (m)(p)(q/n) 7/69@23/24$ , other than the confusing $ = 7(23)(24/69) = 56
*April 6, 2016*

**Math**

What's wrong with just plugging in the numbers and adding the fractions?
*April 6, 2016*

**math**

the last one looks just like http://www.jiskha.com/display.cgi?id=1459986016 but you changed the first term so the answer is not 2779 like in your previous question for the bagel question, which I did for you here http://www.jiskha.com/display.cgi?id=1459985491 how did you get...
*April 6, 2016*

**Math**

A(2) = 3 - 2(2)^2 - 4^2 = 3 - 8 - 16 = -21 find A(1) the same way, then subtract them
*April 6, 2016*

**Geometry**

Follow my steps in your previous post http://www.jiskha.com/display.cgi?id=1459994336
*April 6, 2016*

**Trig**

let the length of the chord be 2x ft Drop a perpendicular from the central vertex to the chord then sin 12.5 = x/30 x = 30sin12.5 2x = 60sin12.5 = 12.9864 or by cosine law: let the length of the chord be c c^2 = 30^2 + 30^2 - 2(30)(30)cos25 = 168.64598.. c = 12.9864 , same as ...
*April 6, 2016*

**Geometry**

let the width of the uniform border be x ft new width = 10+2x new length = 15 + 2x area of whole thing = (10+2x)(15+2x) (10+2x)(15+2x) - 150 = 100 150 + 50x + 4x^2 - 15 - 100 = 0 4x^2 + 50x - 100 = 0 2x^2 + 25x - 50 = 0 doesn't factor, so use the formula x = (-25 ±...
*April 6, 2016*

**Math**

let number of boys be 5x let numbe of girls be 3x after change: boys --- 5x+1 girls --- 3x+3 (5x+1)/(3x+3) = 4/3 15x + 3 = 12x + 12 3x = 9 x = 3 new class : boys = 16 girls = 12 total = 28
*April 6, 2016*

**math**

-3/4-(3/-8) = -3/4 + 3/8 = -6/8 + 3/8 = -3/8
*April 6, 2016*

**correction - Math**

scrap the 7,5,1,1 combination, they don't add up to 12 also scrap the 7,1,1,1,1, there should only be 4 digits.
*April 6, 2016*

**Math**

add = odd ?? notice that 12 = 7+5+1+1 or 12= 3+5+3+1 12 = 7+3+1+1 12 = 9+1+1+1 see if you can find any others. now each of my choices can be arranged in different orders 7,5,1,1 ---> yields 4!/2! or 12 of them 3,5,3,1, yields 4!/2! = 12 of them 7,1,1,1,1 etc one of them is ...
*April 6, 2016*

**Geometry**

Algebraic way: original width = x original length = 2x+3 x(2x+3) = 434 2x^2 + 3x - 434 = 0 (x - 14)(2x + 31) = 0 x = 14 or x = -31/2 , which I will reject original width is 14 ft original length is 31 ft new width = 18 new length = 35
*April 6, 2016*

**Algebra**

notice for each increase of 2 units of tem, the level drops 10 rate of change = -10/2 ft/h = -5 ft/hr
*April 6, 2016*

**Algebra**

between which readings ?
*April 6, 2016*

**Geometry**

ok, ok I stand corrected, there is a way, we have an angle. The apothem is the distance from the centre to the midpoint of a side Let's look at one of the triangles of the hexagon. It has a central angle of 60 so in a right-angled triangle formed by the apothem and half ...
*April 6, 2016*

**Geometry**

So, I guess we can't find the area, since we need the side
*April 6, 2016*

**Geometry**

Area = 1/2 x perimeter x apothem = 1/2 (6s)(6√3) once you tell me what the side (s) of the hexagon is, we an finish the question
*April 6, 2016*

**Algebra**

confusing wording Anyway, for y = mx + b m is the slope, or the rate of change the greater the value of m, the greater the rate of change.
*April 6, 2016*

**math**

looks like an AS with a = 4.5 and d= .5 term(5550) = a + 5549d = 4.5 + 5549(.5) = ....
*April 6, 2016*

**math**

2c + 4b = 600 2c + 7b = 825 subtract them: 3b = 225 b = 75 sub b = 75 back into the firs equation and solve for c let me know what you get.
*April 6, 2016*

**Precal**

We don't "work this out" I believe this is an identity, so we have to prove LeftSide = RightSide If it is an identiy, if we attempt to "solve" it, we end up 0=0 LS = cot^3 x+ cotx = cotx(cot^2 x + 1) = (cosx/sinx)((cos^2 x/sin^2 x + 1) = (cosx/sinx)(cos...
*April 6, 2016*

**Algebra**

credit cards with 7.5% and 6% interest rates? Must be some alternate universe. Anyway... amount charged at 6% card --- x amount charged at other card -- 2x .06x + .075(2x) = 840 .06x + .15x = 840 .21x=840 x = 4000 She charges $4000 at the 6% card and $8000 at the 7.5% card
*April 6, 2016*

**College Algebra**

A, C, and D are correct B: 3f(-1) = 3[(-1)^2 + 3(-1)] = 3[1 - 3] = 3(-2) = -6 E) x^2 + 3x = 4 x^2 + 3x - 4 = 0 (x+4)(x-1) = 0 x = -4 or x = 1 checking for x = -4 f(-4) = (-4)^2 + 3(-4) = 16-12 = 4 , checks! try for x = 1 the same way, you should get 4 as well
*April 6, 2016*

**Trigonometry**

You will have to use a calculator for this one. if cosx = .1 then x = 84.26° correct to 2 decimals but cosine is positive in I or IV so x = 360-84.26 = 275.74° x = appr 84.26 or 275.74
*April 5, 2016*

**maths**

adding/subtracting of degrees works like add/subtract in units of time we have to "borrow" a degree 22degrees33' - 10degrees54' = 21° 93' - 10° 54' = 11° 39' look at your calculator If you have a key labeled D°M'S then you can ...
*April 5, 2016*

**Probability (check)**

That would be 4C2 , four choose two, or C(4,2) = 4!/(2!2!) = 6
*April 5, 2016*

**Algebra**

(4y^2z^3-8yz^2)/(yz^2-2z) = 4yz^2(yz - 2)/(z(yz - 2)) = 4yz^2/z = 4yz , z ≠ 0, yz ≠ 2
*April 5, 2016*

**math**

following BEDMAS 3/8 * 1/4 / 3/4 + 1/5 = 3/32 / 3/5 + 1/5 = 1/8 + 1/5 = 13/40
*April 5, 2016*

**math**

let his gain in third month be x -15.45 + 35.68 + x = 40 x = 19.77
*April 5, 2016*

**calculus**

let y = √( 25-x^2) = (25-x^2)^(1/2) dy/dx = (1/2)(25-x^2)^(-1/2) (-2x) = -x/√(25-x^2) = 0 for a max/min thus x = 0 and f(0) = √25 = 5 I will let you decide if (0,5) is a max or a min You might want want to look at a quick sketch of the function to easily ...
*April 5, 2016*

**calculus**

If you are studying Calculus, you should make an effort to memorize the ratios of two important triangles: 1. the 45-45-90 degree triangle, with sides 1 : 1 : √2 corresponding to the angles 2. the 30-60-90 degree triangle, with sides 1 : √3 : 2 so in this case if ...
*April 5, 2016*

**college algebra**

R = k L/d^2 given case: L = 300, d = .05, R = 30 30 = k (300/.05^2) k = .0025(30)/300 = .00025 R = .00025 L/d^2 a) plug in the given values to find R b) plugging in our values: 20 = .00025 L/.03^2 L = .0009(20)/.00025 = 72 the wire is 72 inches long
*April 5, 2016*

**math**

3 miles take 27 minutes 1 mile would take 27/3 or 9 minutes thus 10 miles would take 90 minutes
*April 5, 2016*

**math**

Use the distance between 2 points formula It is in your text or in your notes
*April 4, 2016*

**Math PLZ**

x and y are whatever YOU define them as. For this question, using 2 variables is more difficult than using just one I would let x be the number of dimes. then the number of nickels is x+4 (it said so) Now form your equation using the value of those coins 10x + 5(x+4) = 95 15x...
*April 4, 2016*

**Pre-Algebra**

prob(getting a 4 ) = 1/6 so in 200 tries, number of times a 4 should show up = (1/6)(200) = 33 1/3 It said "about" how many times, so I would say about 33 times
*April 4, 2016*

**Algebra**

number of subsets for 3 elements = 2^3 = 8 which would include the null set and the entire set. So we have to include the null set {}, and the entire set {3,7,2}
*April 4, 2016*

**Math**

If you have to use all 9 coins, the solution you gave is the only one to produce 60 cents, and use all 9 coins If you can use any number of your 9 coins, then 2 quarters 1 dime 0 pennies would be an option To prove that there is only 1 way using all 9 coins, consider this ...
*April 4, 2016*

**Math**

Damon, I still have mine ! btw, that should have been log3 (5m)
*April 4, 2016*

**Trigonometry**

if sinx = 4cosx sinx/cosx =4 tanx= 4 = 4/1 sketch a right-angled triangle with opposite 4 and adjacent 1 then r^2= 4^2 + 1^2 r = √17 then sinx = 4/√17 , cosx = 1/√17 sinxcosx = (4/√17)(1/√17) = 4/17
*April 4, 2016*

**Math/Algebra**

just use a simple ratio x/420 = 1/(5/6) = 6/5 cross-multiply 5x = 2520 x = 504
*April 4, 2016*

**geometry**

Well, you said it was a right-angled triangle, so the largest angle is 90° the sum of the other two must be 90° 3x+4 + 4x+2 = 90 solve this simple equation for x, then sub in the 2 different expressions
*April 4, 2016*

**Math**

to get a sum of 5, we could have 1 4 2 3 3 2 4 1 so, prob(sumof 5) = 4/36 expected sum of 5 in 72 tries = (4/36)(72) = 8
*April 4, 2016*

**Transformations ALGEBRA**

to shift "up" 2 units, add 2 to the function f(x) = |x| + 3 + 2 f(x) = |x| + 5 What do you think we should do if we shift it 4 units down ?
*April 4, 2016*

**Algebra**

let the "certain" speed be x km/h then the distance between the two cities is 4x km time for return trip = 100/x + (4x-100)/(x-10) 100/x + (4x-100)/(x-10) - 4 = 1/2 100/x + (4x-100)/(x-10) = 9/2 multiply each term by 2x(x-10), the LCD 200(x-10) + 2x(4x-100) = 9x(x-10...
*April 4, 2016*

**Math Algebra 2**

I did this in a rather lengthy series of steps here. Steve has a more simplified version and also found an typo in mine http://www.jiskha.com/display.cgi?id=1459772906 my last 3 lines should have been v^2 = (c^2 m^2 - m0^2c^2)/m^2 v^2 = c^2 - m0^2c^2/m^2 v = c√(1 - m0^2/...
*April 4, 2016*

**Math-soh cab toa**

so 70 would be the hypotenuse of your right-angled triangle and you want the height, which is opposite your angle of 30° According to SOHCAHTOA sin30° = h/70 h = 70sin° = ....
*April 4, 2016*

**math**

Ms Sue and I both did this for you
*April 4, 2016*

**math**

distance = rate x time = 40(3.5) = 140 km Mmmmmhhhh, I doubt if you can get from Paris, France to London England in 3.5 hrs going at 40 km/h However, in southern Ontario where I live, there are a London and a Paris which happen to be about 100 km apart.
*April 4, 2016*

**math**

she did (4.6/48) miles/min = .0958.. miles/min or = 5.75 mph
*April 4, 2016*

**math**

That's the way the standard formula is. notice I had the correct answer.
*April 4, 2016*

**math**

That's a very creative formula you have there, but it makes no sense to me. You want the present value of monthly payments of $350 for 20 years at 6% compounded monthly PV = 350(1 - 1.005^-240)/.005 = 48,853.27 Btw, your P value turns out to be 319.50 Did you find that ...
*April 4, 2016*

**math**

Yes, I am one of the volunteer tutors on this site, we do not any definite time when you will find us. I answer mostly Math questions
*April 4, 2016*

**math**

if a sine of cosine curve is of the form y = a sin k(θ + c) + p you should memorize what what each of the a, k, c, and p represent None of your given functions have any verical shifts for all of them |a| is the amplitude the period is 2π/coefficient of x the only ...
*April 4, 2016*

**math**

see reply to your post above this one
*April 4, 2016*