Question

What is -4x+11y=15 when x=2 y ?

Answer 1

`x=10`
`y=5`

Explanation:

`-4x+11y=15` --- (1)
`x=2y` --- (2)

Sub (2) into (1)
`-4(2y)+11y=15`
`-8y+11y=15`
`3y=15`
`y=5` --- (3)

Sub (3) into (2)
`x=2y`
`x=2times5`
`x=10`