Question

How do you find the solution of the system of equations `-3x+4y=12` and `3x-6y=18`?

Answer 1

Given
`-3x+4y=12`
`3x-6y=18`

If you add the two equations together, you get
`-2y = 30`
`rarr y=-15`

Plug this back into the first equation:
`-3x + 4(-15) = 12`
`-3x = 72`
`rarr x= -24`

It would be a good idea to check these values with the second equation:
`3(-24)-6(-15) = -72+90 = 18 " and it all looks good!"`