Question

I have to solve this system of equations using substitution. I don't understand how to do this one.

Answer 1

`\begin{gathered} x=-3y+1 \\ -3x-3y=-15 \end{gathered}`

Substitution

`\begin{gathered} -3(-3y+1)-3y=-15 \\ 9y-3-3y=-15 \\ 9y-3y-3=-15 \\ 6y-3=-15 \\ 6y=-15+3 \\ 6y=-12 \\ y=-(12)/(6) \\ y=-2 \end{gathered}`
`\begin{gathered} x=-3y+1 \\ x=-3(-2)+1 \\ x=6+1 \\ x=7 \end{gathered}`

The answer would be x = 7 and y = -2