Question

Solve each system by elimination.
-4x + 8y = -24
7x - 5y = 24

Answer 1

The solution is the point (2,-2)

Explanation:

we have

`-4x+8y=-24` -----> equation A

`7x-5y=24` -----> equation B

step 1

Multiply by 7 equation A both sides

`7(-4x+8y)=7(-24)`

`-28x+56y=-168` -----> equation C

step 2

Multiply equation B by 4 both sides

`4(7x-5y)=4(24)`

`28x-20y=96` -----> equation D

step 3

Adds equation C and equation D

`-28x+56y=-168\\28x-20y=96\\-----------\\56y-20y=-168+96\\36y=-72\\y=-2`

Find the value of x

substitute the value of y in any equation

equation A

`-4x+8(-2)=-24\\4x=-16+24\\4x=8\\x=2`

therefore

The solution is the point (2,-2)