You can simplify the equation:
[tex]v(x)=12-7x[/tex]To find the solution in a value of x you substitute the x by the given value:
x=-2
[tex]\begin{gathered} v(-2)=12-7(-2) \\ v(-2)=12+14 \\ v(-2)=26 \end{gathered}[/tex]x=0
[tex]\begin{gathered} v(0)=12-7(0) \\ v(0)=12 \end{gathered}[/tex]x=5
[tex]\begin{gathered} v(5)=12-7(5) \\ v(5)=12-35 \\ v(5)=-23 \end{gathered}[/tex]