Question

Solve the equation by using the Quadratic Formula.

𝑥^2+8⁢𝑥+15=0
Simplify your solutions. If the solutions are real rational numbers, list from least to greatest separated by a comma. If the solutions are not real numbers, write your answer in the form a ± bi. If the solutions are irrational, write your answer in simplified radical form, using ± to express both solutions.

Answer 1

Use the quadratic formula x = [-b ± sqrt(b^2 − 4ac)]/(2a) with a=1, b=8, c=15:

x = [-8 ± sqrt(64 − 60)]/2 = [-8 ± sqrt(4)]/2 = [-8 ± 2]/2.

Thus x = (-8−2)/2 = -5 or x = (-8+2)/2 = -3.

Answers (least to greatest): -5, -3.