Question

How do you solve the following linear system: `3x - 6y = 9 , 6y = 4x + 15`?

Answer 1

`x=-24`
`y=-27/2`

Explanation:

`3x-6y=9` --- (1)
`6y=4x+15` --- (2)

From (1)
`3x-6y=9`
`x-2y=3`
`x=2y+3` --- (3)

Sub (3) into (2)
`6y=4(2y+3)+15`
`6y=8y+12+15`
`-2y=27`
`y=-27/2` --- (4)

Sub (4) into (3)
`x=2(-27/2)+3`
`x=-27+3`
`x=-24`