Question

Solve 0 = 5x2 – 1.5x – 0.5 by using the graphing calculator to graph the related function. What are the solutions to the equation?

–0.5 and 0.2
–0.2 and 0.5
–0.5 and 0.5
–0.2 and –0.5

Answer 1

Use the quadratic formula: x = [1.5 ± sqrt((−1.5)^2 − 4·5·(−0.5))]/(2·5).
Discriminant = 2.25 − (−10) = 12.25, sqrt = 3.5.
So x = (1.5 ± 3.5)/10 → x = 0.5 or x = −0.2.

Answer: −0.2 and 0.5.