Question

How do you solve `2x-y=-10` and `2x-4y=-4`?

Answer 1

`x=-5/2`

`y=-2`

Explanation:

`2x-y=-10" "color(red)(2x)=y-10" (1)"`

`2x-4y=-4" "color(red)(2x)=4y-4" (2)"`

`(1)=(2)`

`y-10=4y-4`

`-10+4=4y-y`

`-6=3y`

`y=-6/3`

`y=-2`

`"using (1) or (2)"`

`2x=y-3`

`2x=-2-3`

`2x=-5`

`x=-5/2`