Question

Solve the following system of equations using substitution x-3y=5-4x+y=-9

Answer 1

Given:

x-3y=5 ....(1)

-4x+y=-9 ....(2)

From equation (1),

`x=5+3y\ldots.\text{ (3)}`

Substitute x=5+3y in equation (2),

`-4(5+3y)+y=-9`
`-20-12y+y=-9`
`-11y=-9+20`
`y=(11)/(-11)`
`y=-1`

Substitute y=-1 in equation (3),

`x=5+3(-1)`
`x=5-3`
`x=2`

Therefore, (x,y) = (2,-1)