What is the y-value of the vertex of the function f(x) = –(x + 8)(x – 14)?

so we want to know the vertex point of the equation f(x)=-(x+8)(x-14). First lets simplify the equation: f(x)=-x^2+6x+112. Now lets calculate the vertex by transforming the function to the form: f(x)=a(x-h)^2 + k where h and k are vertex coordinates. So: f(x)= (-x^2+6x+9)+121=-(x-3)^2+121 and the vertex point is (3,121).

You would plot 83 on the 83 line and you would plot -113 on the -113 line.