y + 8x = -x² - 13

y = -x² - 8x - 13

-x² - 8x - 13 = 0

x² + 8x + 13 = 0 ← divided by -1

x² + 8x = -13 ← subtracted 13

x² + 8x + 16 = -13 + 16 ← took half of 8, squared, and added to each side

(x + 4)² = 3 ← factored left side

x + 4 = ±√3 ← took square root of each side

x = -4 ± √3 ← subtracted 4

- Proof

**
**