Question

How do you write `f(x)= -3x^2 +12x -11` in vertex form?

Answer 1

y = -3(x - 2)^2 + 1

Explanation:

x-coordinate of vertex:
x = -b/(2a) = -12/-6 = 2
y-coordintae of vertex:
y(2) = -12 + 24 - 11 = 1
Vertex form:
y = -3(x - 2)^2 + 1
Check.
Develop y to get back to standard form:
y = -3(x^2 - 4x + 4) + 1 = -3x^2 + 12x - 11. OK