Checkpoint: Writing Quadratic Functions Given Three Points Solution

Verify the equation in Example 7 is correct using the given points. Explain.

$(1, 5.5) 5.5 = 0.5 {(1)}^{2} - 4 (1) + 9 5.5 = 5.5$

$(- 2, 19) 19 = 0.5 {(- 2)}^{2} - 4 (- 2) + 9 19 = 19$

$(3, 1.5) 1.5 = 0.5 {(3)}^{2} - 4 (3) + 9 1.5 = 1.5$

The quadratic equation is correct because all of the points create true statements.