Answer:
x = -2 + √19, x = -2 - √19
Step-by-step explanation:
Equation: x² + 4x = 15
Complete the square of ax² + bx: x² + 4x + 4
Insert into equation (with balancing): x² + 4x + 4 = 15 + 4
Change form: (x + 2)² = 15 + 4
Combine like terms: (x + 2)² = 19
Square root: x + 2 = ±√19
Isolate x: x = -2 ± √19
