Question

How do you solve the following system?: `7y=4- 2x , 2x – y = -4`

Answer 1

To solve, rearrange one equation so that one variable is the subject, then substitute that equation into the other equation, and solve from there.

Explanation:

Example method for this question would be:
`(1)` `7y=4-2x`
`(2)` `2x-y=-4`
rearrange `(2)` to give:
`(3)` `2x=y-4`
substitute `(3)` into `(1)`:
`7y=4-(y-4)`
`8y=8`
`y=1`
Then substitute `y=1` into `(2)`
`2x-1=-4`
`2x=-3`
`x=-3/2`

Check by substituting both into `(1)`.
`7=4+3`