Question

How do you solve the system of equations: 3x - y = 8, y = x - 4?

Answer 1

The solutions are
`color(blue)(x=2,y=-2`

Explanation:

`3x - y = 8`........equation `1`
`y =color(blue)( x - 4`..........equation `2`

Solving by substitution .

Substituting equation `2` in equation `1`
`3x -( color(blue)( x - 4) )= 8`

`3x - color(blue)( x + 4 )= 8`
`2x +4 = 8`
`2x = 4`
`color(blue)(x = 2`

Finding `y` by substituting `x` in equation `2`
`y =x - 4`
`y =2 - 4`
`color(blue)(y=-2`