Question

If 8x−4y=20 and 4x−8y=4, what is the value of x−y

Answer 1

x-y=3-1=2

Explanation:

`8x-4y=20`
`4x-8y=4`

`8x=20+4y`
`4((20+4y)/(8))-8y=4`

`x=(20+4y)/(8)`
`(80+16y)/(8) -8y=4`

`x=(20+4)/(8)`
`10+2y-8y=4`

`x=(24)/(8)`
`10-6y=4`

`x=3`
`-6y=4-10`

`-6y=-6`

`y=1`

so x-y=3-1=2