Question

Pls pls pls answer! I will mark brainliest!!!! tysm xy = 72 (x + 2)(y - 4) = 128

Answer 1

Answer:

x=2 and y=36

Step-by-step explanation:

you have two equations

1) xy=72 and 2) (x+2)(y-4)=128

solve for one of the variables in equation 2), lets do y

(x+2)(y-4)=128, divide by (x+2) to both sides and add 4 to isolate variable y

therefore, y=(128/(x+2))+4

then plug in y into equation 1)

so x(our new y)=72

x( 128/(x+2) +4 )=72

distribute the x so you will get

(128/(x+2))x +4x=72

we are now solving for x, so isolate the x by subtracting 4x and multiplying by (x+2) to get

128x=(x+2)(72-4x)

multiply by distribution and combine like terms

-4x^2 -64x +144 =0

solve for x by quadratic formula, you'll get x=2 or x=-18

substitute back into equation 1), (2)(y)=72, solve for y to get 36

then you can check by substituting back into equation 2)

(2+2)(36-4)=128

(4)(32)=128, 128=128