Answer
See image:
Work Step by Step
$ \begin{array}{llll}
\text{Function:} & f(x)=x^{2}-10x-600 & & \\
\text{coefficients} & a =+1, b=-10, c=-600 & & \\
\text{coefficient a} & \text{positive, opens up} & \\ & \\
\text{Vertex} & x_{V}=-b/(2a) & y_{V}=f(-b/(2a)) & \\
& x_{V}=5 & y_{V}=-625 & \\
& \bf V(5,-625) & & \\\\
\text{Line of symmetry} & x=5 & & \\
\text{y intercept} & c=-600, & \bf(0,-600) & \\
\text{point symmetric to } & & & \\
\text{the y-intercept} & x=2x_{V}=10 & \bf(10,-600)\\ & \\
\text{Zeros:} & f(x)=0 & & \\
& x^{2}-10x-600=0 & [30\times(-20)=-600] & \\
& (x+30)(x-20)=0 & [30+(-20)=10] & \\
& x=-30, x=20 & & \\
& \bf(-30,0), (20,0) & &
\end{array}$
Additional points: $(40,600), (-30,600).$
Using the above information, plot the points and join with a smooth curve (parabola).