Question

How do solve the following system of equations: -2x + y = 1 and -4x + y = -1?

Answer 1

I found:
`x=1`
`y=3`

Explanation:

You can try by multiplying the first equation by `-1` and adding the two in columns:
`{(color(red)(-1)xx-2x+y=1),(-4x+y=-1):}`

`{(2x-y=-1),(-4x+y=-1):}` add them:

`-2x+0=-2`

`x=2/2=1`

use this back into the first equation:
`-2*1+y=1`
`-2+y=1`
`y=3`