Answer :
Given equation is,
[tex]v=-(x-3)(x+1)[/tex][tex]\begin{gathered} v=-(x-3)(x+1) \\ v=(-x+3)(x+1) \\ v=-x^2-x+3x+3 \\ v=-x^2+2x+3 \end{gathered}[/tex]Now, let us solve the above equation.
[tex]\begin{gathered} v=-x^2+2x+3 \\ v=-(x^2-2x-3) \\ v=-(x^2-2x+(-1)-(-1)-3) \\ v=-((x-1)^2-(-1)^2-3) \\ v=-((x-1)^2-4 \\ v=-(x-1)^2+4 \end{gathered}[/tex]the vertex is at (1,4)