ANSWER:
The value of x is 2 and of y is 4
[tex](2,4)[/tex]STEP-BY-STEP EXPLANATION:
We have the following equation system
[tex]\begin{gathered} y=4 \\ -2x+4y=12 \end{gathered}[/tex]solving for substitution:
[tex]\begin{gathered} -2x+4\cdot4=12 \\ -2x+16=12 \\ -2x=12-16 \\ x=\frac{-4}{-2} \\ x=2 \end{gathered}[/tex]