4.2 – Graph Quadratic Functions in Vertex or Intercept Form

Standard Form: y = ax2 + bx + c

Vertex Form: y = a(x – h)2 + k

4.2 – Graph Quadratic Functions in Vertex or Intercept Form

Example 1: Graph a quadratic function in vertex form

Graph y = -1/4(x+2)2 + 5

4.2 – Graph Quadratic Functions in Vertex or Intercept Form

Example 2: Graph a quadratic function in vertex form

Graph y = (x+1)2 – 3

4.2 – Graph Quadratic Functions in Vertex or Intercept Form

Example 3: Graph a quadratic function in vertex form

Graph y = (x - 4)2 + 5

4.2 – Graph Quadratic Functions in Vertex or Intercept Form

If the graph of a quadratic function has at least one x-intercept, then the function can be represented in

intercept form, y = a(x – p)(x – q)

4.2 – Graph Quadratic Functions in Vertex or Intercept Form

Example 4: Graph a quadratic function in intercept form

Graph y = 2(x + 3)(x – 1)

4.2 – Graph Quadratic Functions in Vertex or Intercept Form

Example 5: Graph a quadratic function in intercept form

Graph y = -(x + 1)(x – 5)

4.2 – Graph Quadratic Functions in Vertex or Intercept Form

Example 6: Graph a quadratic function in intercept form

Graph y = -x(x - 4)

4.2 – Graph Quadratic Functions in Vertex or Intercept Form

Example 7: Graph a quadratic function in intercept form

The path of a placekicked football can be modeled by the function y = -0.026x(x – 46) where x is the

horizontal distance (in yards) and y is the corresponding height (in yards).

a. How far is the football kicked?

b. What is the football’s maximum height?