Question

What is the vertex of the graph of the function f(x) = x2 + 8x − 2 ?

Answer 1

Given : Function f(x) = x² + 8x - 2

To find : Vertex of the given function.

Solution : f(x) = x² + 8x - 2

                     = x² + 2(4)x - 2

                     = x² + 2(4)x + 4²- 4² - 2

                     = [x² + 2(4)x + 4²] - 16 - 2  

                     = (x + 4)² - 18

This is the vertex form of the of the function which is in the form of

f(x) = (x - h)² + k

Here (h, k) is the vertex.

Therefore, Vertex of the given function is (- 4, -18).