Question 968610
Student could have gave minus sign instead of "equals" sign.
{{{f(x)=x^2-10x-30}}}
and wants vertex, and know if max or min.


Try completing-square.
{{{(10/2)^2=25}}};
add and subtract from, to the quadratic expression.


{{{x^2-10x-30+25-25}}}

{{{x^2-10x+25-30-25}}}

{{{(x-5)^2-55}}}

{{{highlight(f(x)=(x-5)^2-55)}}}

vertex point at  (5, -55) and is a minimum.