Question

X-y=3x+y=5unit 7 systems of linear equations

Answer 1

`\begin{gathered} \begin{bmatrix}x-y=3 \\ x+y=5\end{bmatrix} \\ x-y=3 \\ x-y+y=3+y \\ x=3+y \end{gathered}`

then

`\begin{gathered} x+y=5 \\ 3+y+y=5 \\ 3+2y=5 \\ 3+2y-3=5-3 \\ 2y=2 \\ (2y)/(2)=(2)/(2) \\ y=1 \end{gathered}`

solve for x

`\begin{gathered} x=3+y \\ x=3+1 \\ x=4 \end{gathered}`

answer: C. (4,1)