Answer:
x = -2.5 ± √14.25
Step-by-step explanation:
Add 5x to prepare for "completing the square."
x² +5x = 8
Add the square of half the x-coefficient:
x² +5x + 2.5² = 8 + 2.5²
(x +2.5)² = 14.25
Take the square root.
x +2.5 = ±√14.25
Subtract 2.5.
x = -2.5 ± √14.25 ≈ {-6.27492, 1.27592}