Question

How do you solve by substitution `x - 2y = -1` and `2x - y = 4`?

Answer 1

The solution for the system of equations is
`color(blue)(x = 3 , y =2`

Explanation:

`x - 2y = -1`
`x =color(blue)( -1+2y`........equation `(1)`

`2x - y = 4`............equation `(2)`

Substituting equation `1` in `2` to find `y`
`2color(blue)((-1+2y)) - y = 4`
`-2 +4y -y = 4`
`3y =6`
`color(blue)(y=2`

Substituting `y` in equation `1` to find `x`:
`x = -1+2y`
`x = -1+4`
`color(blue)(x = 3`