Question

Solve for the roots using the quadratic formula. Express your answers to two decimal places.

2x^2 − 5x − 1 = 0

Answer 1

x = 2.69 or x = -0.19

Explanation:

Given:

2x² − 5x − 1 = 0

x = {-b ± √b² - 4ac} / 2a

a = 2

b = -5

c = -1

x = {-b ± √b² - 4ac} / 2a

= {-(-5) ± √(-5)² - 4(2)(-1)} / 2 * 2

= {5 ± √25 - (-8)} / 4

= {5 ± √25 + 8} / 4

= 5 ± √33 / 4

= 5 ± 5.75 /4

x = 5/4 + 5.75/4 or x = 5/4 - 5.75/4

x = 10.75/4 or x = -0.75/4

x = 2.69 or x = -0.19