Question

What is the axis of symmetry for f(x) = −3x2 + 18x − 7?

Answer 1

The formula for axis of symmetry is $- \frac{b}{2a}$.
We insert the values into our function. :$- \frac{18}{2(-3)}$ This equals $- \frac{18}{-6} =3$
x=3 is the axis of symmetry. 

Answer 2

3 is the axis of symmetry because of the equatio -b/2a and since two negatives simplyfy this becomes a positive