Question 65159
{{{f(x) = x^2 - 6x}}}
{{{f(x) = x(x - 6)}}}
The intercepts are (0 , 0) and (6 , 0)
The axis of symmetry will be midway between x = 0 and x = 6
which would be x = 3
{{{f(x) = 3^2 - 6*3}}}
{{{f(x) = 9 - 18}}}
{{{f(x) = -9}}}
So  the vertex is at (3 , -9)