​Quadratic Function

​Earlier we saw that the graph of y=x² is a parabola.

The function P(x) = x² is the simplest form of a quadratic function.

​Example 1

​P(x) = x² - 2x - 15

P(x) + 15 = x² - 2x

P(x) + 15 + 1 = x² - 2x + 1

P(x) + 16 = (x - 1)²

P(x) = (x - 1)² - 16

​Write the function in the form y = a(x-h)²+k

​1. Add 15 to both sides

2. Take (1/2*b) and square it. Add result to both sides

3. Factor the right side

4. Subtract 16 back to other side