Question

What is the vertex of g(x) = –3x2 + 18x + 2?

Answer 1

g(x)=1
-3x2+18x+2
-6+18+2
6+2
8

Answer 2

The vertex of g(x) is (3;29)

Explanation:

The coordinates of the vertex for a cuadratic equation are defined as:

Xv = -b/2a

Yv = f(Xv)

Where b, and a correspond to the coefficients of the linear and cuadratic terms respectively. In this particular case f(x) is represented by g(x).

Then by replacing the coefficients a and b in the x-coordinate we obtain:

Xv = -18/ (2.-3) = -18 / -6 = 3

And by replacing Xv in g(x):

Yv = g(Xv) = -3(3)^2 + 18(3) + 2

Yv = -27 + 54 + 2 = 29

Thus the vextex of g(x) is (3:29)