Question

Find the vertex of the parabola formed by the following quadratic function y = -3x2 + 12x – 7

Answer 1

y'= -6 x + 12

Answer 2

y'=0 when x=2

Answer 3

(2, y(2)) is vertex

Answer 4

(2,5) is the vertex

Answer 5

If you do not know derivatives, you complete the square and obtain
\[
y=-3 x^2+12 x-7=-3 \left(x^2-4
x+4-4\right)-7=-3 (x-2)^2+5
\]
If x =2, y=5