Question

Section 5.2-10. Solve the following system of equations by substitution or elimination. Enter your answer as (x,y).-2x+3y = 15-x-3y = 12

Answer 1

`-2x+3y=15\ldots\ldots1)`
`-x-3y=12\ldots\ldots\ldots\ldots\text{2)}`

1)-2x2)

`-2x+3y-(-2x-6y)=15-2*12\Rightarrow-2x+3y+2x+6y=15-24\Rightarrow9y=-9\Rightarrow y=-1`

y=-1 implies

`-2x+3*(-1)=15\Rightarrow-2x-3=15\Rightarrow-2x=18\Rightarrow x=-9`

Hence the solution is

`(-9,-1)`