Question

g(x) = -x2 - 2x + 3 find the vertex.

Answer 1

find the derivative,equate to 0 and find the values of x . I guess that will help .

Answer 2

if you havent done any calculus then do it this way
x cood of vertex = b/2a
= -2 / 2 = -1
y cood = -(-1)^2 - 2(-1) + 3 = 4

vertex is at (-1,4)