Question

How do you solve the system `y=3-4x` and `-3x-y=2`?

Answer 1

`y=color(red)(3-4x` ....equation `(1)`
`-3x-y=2`.......equation `(2)`

substituting equation `(1)` in equation `(2)`

`-3x-y=2`
`-3x-color(red)((3-4x))=2`
`-3x color(red)(- 3 +4x)=2`
`x=2 + 3, color(blue)(x = 5`

substituting `x` in equation `(1)` to find `y`
`y=3-4x`
`y=3-20 , color(blue)(y = -17`

the solutions are : `color(blue)( x = 5 , y = -17`