Sunday

November 29, 2015
Total # Posts: 31,850

**calculus**

Make your sketch, it should be a right-angled triangle I will assume that the "when it is 5000" refers to the hypotenuse. Make the necessary changes if otherwise. let the horizontal be 300t, where t is in hrs the vertical is fixed at 3000 let the hypotenuse be h when...
*September 20, 2015*

**Math**

Caillyn now -- x Jared now --- 80-x 8 years ago: Caitlyn = x-8 Jared = (80-x) - 8 = 72 - x translate into MATH: "Jared's age was 3 times Caitlyn's age" 72-x = 3(x-8) solve for x make sure your answer satisfies the given conditions.
*September 20, 2015*

**Math**

amount he had --- x amount he spent = x/3 + x/4 = 7x/12 amount left = x - 7x/12 = 5x/12
*September 20, 2015*

**Math**

here is how I do these ... Since it is already factored we can say that the critical values are: -1,2, and 4 so we have 4 sections on the number line: 1. ≤ -1 2. between -1 and 2 3. between 2 and 4 4. ≥ 4 I then pick a nice number for each section. We don' ...
*September 20, 2015*

**Math**

-10-7(n-3) follow the order of operations, = -10 - 7n + 21 = 11 - 7n
*September 20, 2015*

**Math**

solve for x x(1.0075^240 - 1)/.0075 = 320(1 - 1.0075^-360)/.0075 the denominators will cancel, so x = 320*(1 - 1.0075^-360)/(1.0075^240 - 1) = ... you do the button pushing. Let me know what you get
*September 20, 2015*

**Pre-Calc**

looks like a right-angled triangle horizontal distance = 250(4/60) = 50/3 miles vertical distance = 4 miles hypotenuse --- x x^2 = (50/3)^2 + 4^2 = ....
*September 20, 2015*

**math for managers**

Cyntia --- x Adam ---- 3x Fred ----- 3x - 16 one year ago: Cyntia --- x-1 Adam ---- 3x-1 Fred ----- 3x - 17 at that time "Adam's age was twice the sum of Cynthia's and Fred's age" ---> 3x-1 = x-1 + 3x-17 solve for x check that your answer meets the ...
*September 20, 2015*

**math for managers**

1st number --- x 2nd number --- y 5x + 3y = 47 10x - 4y = 54 double the first: 10x + 6y = 94 10x - 4y = 54 subtract them: 10y = 40 y = 4 back into the first 5x + 3(4) = 47 x = 7
*September 20, 2015*

**Algebra**

smaller ball: 48 in^3 = (2.54^3)(48) cm^3 , (since 1 inch = 2.54 cm) = 786.579 cm^3 ratio of volumes = 5274/786.579 = 6.7 so the 10-pin ball is about 6.7 times the volume of the smaller ball
*September 20, 2015*

**statistics**

choosing 3 of 8 = C(8,3) = 8!/(3!5!) = 56 choosing 4 of 8 = ......
*September 20, 2015*

**incomplete - Math**

missing data
*September 20, 2015*

**math too urgent**

Hint: 75 = 30 + 45
*September 20, 2015*

**math**

a^2 "upon" a + b - a-b "upon" a-b what does "upon" mean, I am not familiar with that mathematical operator.
*September 20, 2015*

**math urgent**

Can't be proven, because it is not true check: LS = tan20 + 4tan20 = 5tan20 = 1.8198... RS = √3 = 1.732... LS ≠ RS
*September 20, 2015*

**Algebra**

I see two negative signs, not three con't confuse -w^2 with (-w)^2 -w^2 = (-1)(w)(w)= -w^2 (-w^2) = (-w)(-w) = +w^2
*September 20, 2015*

**math**

Weight of all packets = 12.5 kg - 2.5 kg = 10 kg = 10000g each packet weight 200 g number of packets = 10000/200 = 50
*September 20, 2015*

**Math**

first arrange them in "standard" form: 3a - 2b = 1 5a - 3b = 3 1st times 3, ----> 9a - 6b = 3 2nd times 2, ---> 10a - 6b = 6 subtract them, a = 3 sub back into 2nd 3b= 5(3) - 3 b = 4 a = 3 , b = 4
*September 19, 2015*

**Math**

We don't know how many take all three, which is our first main question. So in your Venn diagram, place x in the intersection of all three circles. Now look at the intersection of the F and G circles We are told that this is 7 but x are already counted, ("some of whom...
*September 19, 2015*

**algebra**

original speed --- x mph time at original speed = 144/x hrs new speed = x+4 time at new speed = 144/(x+4) 144/x - 144/(x+4) = 1/2 solve for x let me know what you get.
*September 18, 2015*

**Algebra**

see http://www.jiskha.com/display.cgi?id=1441674996
*September 18, 2015*

**Math**

bisect means to divide into two equal parts so angle(LMN) = twice angle(LMO) so just solve: 6x-28 = 2(x+34)
*September 18, 2015*

**math**

This is called "variable abuse" There is absolutely no need to introduce variables if the whole process takes only one step e.g. #8, all you have to say is Cougar's score = 72-15 = 57 (I suppose you want C = 72-15 = 57) every one of your problems takes only one ...
*September 18, 2015*

**Algebra**

mmhh, how about 3x/12 - 7/12 now simplify the first term
*September 18, 2015*

**Rectangle**

I agree with Bob I interpreted it as the numerical value of the area minus the numerical value of the perimeter is 9 The question is definitely poorly worded.
*September 18, 2015*

**Rectangle**

perimeter = 2x + 2y, if x and y are length and width area = xy xy - 2x - 2y = 9 xy - 2y = 9 + 2x y(x-2) = 9+2x y = (9+2x)/(x-2) , clearly x>2 if x = 3, y = 15 area = 45, perimeter = 36 , bigger by 9, ✔ performing a long algebraic division, we can see that (9x+2)/(x-2...
*September 18, 2015*

**Math**

the common points are C and G, so yes
*September 18, 2015*

**Math**

Two angles whose sides are opposite rays are called _____ angles So they must form a straight line, ---> supplemetary angles add up to 180°, which is the case Two coplanar angles with a common side, a common vertex, and no common interior points are called ____ angles...
*September 18, 2015*

**math**

all your questions are correct, except the two you could not do first of all, let's clear up that last one. you ended up with -17 = 11 This of course is false even though you made no errors in your solution. If that happens , and you end up with an absurd conclusion like ...
*September 18, 2015*

**ALGEBRA**

Vincent, you expect us to do a lot of problems for you We call that homework dumping. Before I do any more, tell me where your problem lies, or show me your preliminary steps.
*September 18, 2015*

**ALGEBRA**

amount of skimmed milk added --- x L .035(3) +0.0x = .02(x+3) .105 = .02x + .06 .02x = .045 x = 2.25 add 2.25 L check: 3.5% of 3 L is .105 L of fat adding 2.25 L of no fat milk gives us 5.25 L containing still only .105 fat rate of fat = .105/5.25 = .02 as required
*September 18, 2015*

**ALGEBRA**

number of nickels --- n number of dimes ---- d number of pennies --- n+d n + d + n+d = 90 2n+2d = 90 n+d = 45 or d = 45-n value equation: 5n + 10d + 1(n+d) = 285 6n + 11d = 285 using substitution: 6n + 11(45-n) = 285 6n + 495 - 11n = 285 -5n = -210 n = 42 d = 45-42 = 3 so we ...
*September 18, 2015*

**math**

check mark sign? --- I like that √3 is indeed irrational
*September 18, 2015*

**maths**

This is the same as asking for the highest common multiple 8= 4x2 12 = 4x3 15 = 3x5 18 = 3x3x2 so we need: 2x2x2x3x3x5 = 360 they will toll together every 360 seconds in 1 hour there are 3600 seconds so they will toll at 360 s, at 720 s, ... at 3600 s that would be 10 (we are ...
*September 18, 2015*

**Math - not zphs**

If the missing side is the hypotenuse, then h^2 = 9^2 + 12^2 if the missing side is NOT the hypotenuse, then 9^2 + h^2 = 12^2 In either case, solve for h
*September 18, 2015*

**Math**

let the capacity of the tank be 1 unit of whatever rate of 1st pipe = 1/30 rate of 2nd pipe = 1/90 combined rate = 1/30+1/90 = 2/45 time at combined rate = 1/(2/45) = 45/2 = 22.5 minutes
*September 18, 2015*

**ALGEBRA**

original --- x x - x/2 - x/6 = 150000 times 6 6x - 3x - x = 900000 2x=900000 x = 450000
*September 18, 2015*

**algebra**

original fraction --- x/(x-4) new fraction = (x+6)/(2x-8) x/(x-4) + (x+6)/(2x-8) = 3 2x/(2x-8) + (x+6)/(2x-8) = 3 (3x+6)/(2x-8) = 3 cross-multiply .... 6x-24 = 3x+6 3x=30 x=10 original fraction is 10/6 check: old fraction = 10/6 new fraction = 16/12 let's add them: 10/6 + ...
*September 18, 2015*

**Trigonometric functions**

let y = cosx dy/dx = -sinx at a max or min, dy/dx = 0 -sinx = 0 sinx = 0 looking at a standard sine curve x = 0, π, 2π, 3π, ... when x = 0 , f(0) = cos0 = 1 when x = π, f(π) = cosπ = -1 wehn x = 2π, f(2π) = +1 when x = 3π, f(3π...
*September 18, 2015*

**physics**

distance covered at first speed = 60 km distance covered at 2nd speed = 40 km total distance = 100 km total distance = 2 hrs avg speed = 100/2 = 50 km ahhh, looks like we just have to average the speed. Not so fast grasshopper, this was just coincidence supposed the car went ...
*September 18, 2015*

**Maths**

why are you switching names ? - see previous post
*September 18, 2015*

**Maths**

120 = 10 x 3 x 2 x 2 180 = 10 x 3 x 3 x 2 190 = 10 x 19 the HCF (highest common factor) is 10 I don't know what you mean by GCF, to me it would mean "greatest common factor" which is the same as the HCF Did you mean GCM, (greatest common multiple ?) then it would...
*September 18, 2015*

**Verbales (sacar fórmula)**

I don't speak Spanish, but I can figure out that you want to invest 100000 in A and B, neither over 50000, where one is paying 10%, the other 15% and the annual return is 12000 amount at 10% --- x amount at 15% --- 100000-x .1x + .15(100000-x) = 12000 .1x + 15000 -.15x = ...
*September 18, 2015*

**maths**

follow my hint in your previous post Let me know what you get
*September 17, 2015*

**maths**

work with the know fact that Mathew has 14 then Jemima has 28 and Sally must have 7 and Andrew has 4
*September 17, 2015*

**math**

I am sure Steve meant to type 3x = -3 thus x = -1 and therefore y = 3 just like your textbook said
*September 17, 2015*

**Algebra**

so far he has .2(92+83+85) + 10 = 62 let his mark on the final be x 62 + .3x = 90 .3x = 28 x = 93.3
*September 17, 2015*

**Algebra**

Do you want the area to include the circular base? If so, that's a simple addition of the area of the circle for just the sides, SA = πrl, where l is the slant height l^2 = 5^2 + 12^2 l = 13 SA = π(5)13) = 65π
*September 17, 2015*

**Math**

1 yard = 3 ft so ratio of tile to board = (2/3) : 3 = 2 : 9 area of board = 3 ft by 3 ft = 9 square feet area of tile = (2/3)(2/3) = 4/9 ratio of area of tile : area of board = (4/9) : 9 = 4 : 81
*September 17, 2015*

**Math**

The area is the square of the side. e.g. if the side is 7 units, then the area is 7^2 or 49 square units
*September 17, 2015*

**Math**

What do you mean by "answer these types of questions" What were the instructions?
*September 17, 2015*

**Geometry**

simplest way is to use ratios for the x, (x-1)/(7-x) = 2/1 x-1 = 14-2x 3x = 15 x = 5 for the y, (y-1)/(13-y) = 2/1 y-1 = 26-2y 3y = 27 y = 9 so point P is (5,9) check: AP = √(5-1)^2 + (9-1)^2 = √(16+64) = √80 = 4√5 PD = √((7-5)^2 + (13-9)^2) = &#...
*September 17, 2015*

**MATH PROBABILITY**

prob (defect) = .08 prob (not defect) = .92 prob(12 defective of 200) = C(200,12)(.08)^12 (.92)^188 = (my calculator can't handle the calculations)
*September 17, 2015*

**precalc (check answer)**

are you solving 3 - x^2 = 7 ? if so, then -x^2 = 4 x^2 = -4 no real solution, but x = ±2i
*September 17, 2015*

**Algebra 2**

54 - 3x = x+10 etc
*September 17, 2015*

**Math**

a^2 -1 + 2b - b^2 = a^2 - (b^2 - 2b + 1) = a^2 - (b-1)^2 , now we have a difference of squares = (a + (b-1))(a - (b-1)) = (a+b-1)(a-b+1)
*September 17, 2015*

**math**

Anna's present age ---- x uncle's age------- 6x 12 years from now: Anna = x+12 uncle = 6x + 12 x+12 = (1/3)(6x+12) x+12 = 2x + 4 -x = -8 x = 8 Anna is now 8, the uncle is 48 12 years from now, Anna will be 20 , and uncle will be 60
*September 17, 2015*

**pre algebra**

first speed --- x mph 2nd speed --- x+19 mph d/x = 3 ---> d = 3x d/(x+19) = 2 --- d = 2x + 38 3x = 2x+38 x = 38 first speed = 38 mph 2nd speed = 57 mph check: distance = 3(38) = 114 or 2(57) = 114 time for 1st trip = 114/38 = 3 hrs tiem for 2nd trip = 114/57 = 2 hrs
*September 16, 2015*

**Math teacher**

number of 5 cent stamps --- x number of 8 cents stamps ---- y 5x + 8y = 161 y = (161 - 5x)/8 , clearly 0 < x < 33 after a few tries I got x = 5, y = 17 since the slope is -5/8, other values are: x = 13, y = 12 x = 21 y = 7 x = 29 , y = 2 the smallest sum is 5+17 = 22
*September 16, 2015*

**Don't switch names maths**

show your steps like I did and somebody will take a look at it
*September 16, 2015*

**maths**

Type these type of questions like this: (15x^2 y^3 + 9x^2 y^3)/(8x^2 y^3) = 24x^2 y^3/(8x^2 y^3) = 3 , x≠0, y≠0
*September 16, 2015*

**maths**

Celest's savings --- x priscilla --------1.1x Andrea ------- 1.2(1.1x) solve for x x + 1.1x + 1.32x = 1710
*September 16, 2015*

**Math**

let .1/.6 = 2/x and solve for x do the same with the other ratio
*September 16, 2015*

**Math**

8. lucy's age --- L Bobby's age = L - 11/2 or L - 5 1/2 or L - 5.5 Paul's age = L + 37/8 or L + 4 5/8 or L + 4.625 sum of ages = L - 11/2 + L + 37/8 = 3L - 7/8 9 If the band had 5 members, wouldn't you divide 475 by 5 so if the band has b members each share = ...
*September 16, 2015*

**math**

1. (Seven times a number), added to (the sum of the number and eight). ---> 7x + x+8 = 8x + 8 4. 8.7 less than a number ----> x - 8.7 (if I said "3 less than 8", you would take 8-3 , not 3 - 8, wouldn't you ? ) 7. The quotient of a number and 2 subtracted ...
*September 16, 2015*

**maths**

you would need 10 more people
*September 16, 2015*

**maths**

# of watermelons ---- x # of guavas -------- y # of bananas ------ 100-x-y 50x + 10y + 1(100-x-y) = 500 50x + 10y + 100 - x- y = 500 49x + 9y = 400 remember , x and y must be whole numbers if y = 0 , x = 400/49 , closest integer is 8 if x = 0, y = 400/9 , closest integer is 44...
*September 16, 2015*

**MATH**

just plug in the values.... let me know what you get
*September 16, 2015*

**MATH**

length = area / width (x^2 - 3x + 2)/(2x^2 - 7x + 3) ÷ ((x^2 - 3x - 2)/(2x^2 - 3x - 2)) = (x^2 - 3x + 2)/(2x^2 - 7x + 3) * ((2x^2 - 3x - 2)/(x^2 - 3x - 2) again , factor it = (x-2)(x-1)/((x-3)(2x-1)) * (2x+1)(x-2)/((x-2)(x+1)) = ....
*September 16, 2015*

**MATH**

write it like this: (3xy + 6x^2)/(2y) * (4xy - 2y^2)/(9x^2 y^2) * 1/((4x^2 - y^2) factor it ... = 3x(y + 2x)/(2y) * 2y(2x - y)/(3xy)^2 * 1/((2x-y)(2x+y)) = 1/(3x y^2)
*September 16, 2015*

**Math Check Pleas Thank You**

yes, true
*September 16, 2015*

**Math Check Pleas Thank You**

All correct except #5 the set of integers is a subset of the rationals every integer n can be written as a fraction as n/1
*September 16, 2015*

**Math**

There is a story that a famous German mathematician named Gauss was given this by his elementary teacher to keep the students busy in class. They all started adding like crazy, but little Gauss just looked at it for a while, and quickly got the answer. he added: the first + ...
*September 15, 2015*

**Math**

here is a very old trick: add up the digits of each factor 87---> 8+4 = 12 , do it again --- 1+2 = 3 37 ----> 3+7 = 10 ---> 1+0=1 multiply them : 3*1 = 3 take the answer and add up the digits 3108 ---> 3+1+0+8 = 12 -- 1+2 = 3 same result!, extremely high ...
*September 15, 2015*

**algebra**

do you have a question?
*September 15, 2015*

**Calculus**

let y = (6x^2 + 5x - 3)/(2x^2 - 1) - 3 we can simplify = ( 6x^2 + 5x - 3 - 3(2x^2 - 1) )/(2x^2 - 1) = (5x)/(2x^2 - 1) there will be 2 vertical asymptotes, x = ± 1/√2 graph looks like this, the asymptotes are not drawn http://www.wolframalpha.com/input/?i=simplify...
*September 15, 2015*

**Math**

distance by car -- x distance walking -- y x/40 + y/6 = 25/60 times 120 3x + 20y = 50 on breakdown: distance walking = 3y distance by car = (x+y) - 3y = x - 2y 3y/6 + (x-2y)/40 = 42/60 times 120 again 60y + 3x - 6y = 84 3x + 54y = 84 subtract the two equations, 34y = 34 y = 1 ...
*September 15, 2015*

**intermediate algebra**

Now: Renton --- x Eurekd --- x -16 13 years from now: Renton= x+13 Eureka = x-16 + 13 = x - 3 x+13 = 2(x-3) x+13 = 2x - 6 -x = -19 x = 19 Renton is now 19 Eureka is now 3 check: in 13 years from now, Renton will be 32 Eureka will be 16 , so Renton will be twice as old
*September 15, 2015*

**Trig**

tan 70 = height/1.5 height = 1.5 tan 70° = ...
*September 15, 2015*

**Algebra**

solve for x, the amount to be added x + .08(12) = .16(x+12)
*September 15, 2015*

**Algebra**

What is the solution to 5-t=23? My answer is 18. ---- should be -18 What is the value of b if -7+b=-8? My answer is -1. ✔ What is the solution to 5q=-75? My answer is either -25 or -15. --- can only be -15 What is the solution to -6z=72? My answer is -12. ✔ What ...
*September 15, 2015*

**math**

students from A -- x students from B -- 2x students from C -- 3x total students = 6x girls from C --- 7y total girls ------ 10y total boys ------ 6x-10y "There were 124 fewer boys than girls altogether" ---> girls - boys = 124 ---> 10y - (6x-10y) = 124 20y - 6x...
*September 15, 2015*

**Algebra**

material has base x inches by x inches We are cutting out 3 inches at all 4 corners base of box is (x-6) by (x-6) height of box is 3 volume = 3(x-6)^2 , where x > 6
*September 15, 2015*

**math**

The perimeter is the distance around a region, measured in suitable units of length The perimeter of a circle has its own special name, the circumference here is is and abundance of examples of perimeter https://www.google.ca/search?q=perimeter&es_sm=119&tbm=isch&tbo=u&source=...
*September 15, 2015*

**algebra**

(2/3)*(-6)*5 = -20 the others are correct
*September 15, 2015*

**pre calculus**

I can't see your diagram and don't know where x is, but I will assume that the data results in a right-angled triangle with x as the angle of depression from the ocean's surface to the sub. tanx = 880/1450 = ... x = appr 31.25°
*September 14, 2015*

**math algebra**

use the distributive property, then -3*(4+7) = -3*4 + (-3)*7 , which is d of course the original's answer is -3(11) = -33 your choice of b) would give us -84
*September 14, 2015*

**math**

yes, a denominator of 7 results in a repeating decimal. e.g. 4/7 = .571428571.. with the repeat as 571428 interesting to note: 1/7 = .142857142... 2/7 = .285714285.. etc notice the repeat sequence is the same, it just starts at a different digit try it with the other proper ...
*September 14, 2015*

**Math**

When you say " The wind is blowing west ", I will assume "from" the usual west. Your vector diagram would result in a right-angled triangle. Let the actual speed of the plane be r r^2 = 230^2+85^2 = ... r = √... let the angle be Ø sinØ...
*September 14, 2015*

**Algebra II**

You should know that perpendicular lines have slopes that are negative reciprocals of each other. It is easy to see that the slope of the given x+y=5 is -1 Thus the slope of the new line is +1 that is, it must be y = x + b, where b is the y-intercept. And isn't (0,3) the y...
*September 13, 2015*

**Math**

from the given: a -1/a = 2 let's square both sides (a - 1/a)^2 = 4 a^2 - 2 + 1/a^2 = 4 a^2 + 1/a^2 = 6 starting with (a + 1/a)^2 = a^2 + 2 + 1/a^2 = a^2 + 1/a^2 + 2 = 6+2 = 8
*September 13, 2015*

**Algebra**

So you are evaluating A = c (.5)^(2/5.7) 2/5.7 = appr .350877 so we need (.5)^.350877 If you have a good calculator look for a key function labeled yx, which we usually type as y^x enter the base .5 push that yx button enter .350877 press the = button to get .7841.. multiply ...
*September 13, 2015*

**math**

Didn't you just say that he ran .327 km during the first half ? now round that off to the nearest hundredths.
*September 11, 2015*

**calculus**

looks like the solution to a quadratic equation, which turns out to be a complex number remember that √-1 = i , so (-8 +- sqrt -20)/-6 = (-8 ± 2√5 i)/-6 = (4 ± √5 i)/3
*September 11, 2015*

**Math**

http://www.wolframalpha.com/input/?i=2x-5%E2%88%9Ax-3%3D0
*September 11, 2015*

**geometry**

from 3D = 6R D = 2R from 4S = 6R S = 6R/4 = 3R/2 we know D + S + R = 180° 2R + 3R/2 + R = 180 4R + 3R + 2R = 360 9R = 360 R = 40 S = 60 D = 80
*September 11, 2015*

**Giyani high, math**

the way I read it: new length = 10 + (1/4)(10) = 25/2 new width = 6 + (1/3)(6) = 8 new area = (25/2)(8) = 100 m^2
*September 10, 2015*

**Math**

7x^2+7y-4x^2-4y equals to 3x^2-3y 7x^2+7y-4x^2-4y = 3x^2-3y 7x^2 - 4x^2 - 3x^2 = -3y + 4y - 7y 0 = -6y 6y = 0 y = 0 sub back in 7x^2 + 0 - 4x^2 = 3x^2 - 0 0 = 0 x can be any number, y = 0 eg. let x = 3, y = 0 LS = 63 + 0 - 36 - 0 = 27 RS = 27 - 0 = 27 , works! let x = 3, y = 1...
*September 10, 2015*

**trig**

You said each leg is 5 m, so the other leg is 5 h^2 = 5^2+5^2 = 50 h = √50 or 5√2
*September 10, 2015*

**math**

any perfect cube has 3 equal factors e.g. 216 = 6 x 6 x 6 126n = 2 x 3 x 3 x 7 n so to have triples, we need 2x2, 3, and 7x7 n = 4(3)(49) = 588 our number 126n would be 74088 check: 74088 = (2x2x2)(3x3x3)(7x7x7)
*September 10, 2015*