8² = 64
Using the distributive law:
(x + 6)² = x² + 12x + 36
(x + 3)² = x² + 6x + 9
(x + 6)² = 8² + (x + 3)²
x² + 12x + 36 = 64 + x² + 6x + 9
Subtract x² from both sides:
12x + 36 = 64 + 6x + 9
Subtract 6x from both sides:
6x + 36 = 64 + 9
Subtract 36 from both sides and simplify:
6x = 37
Divide by 6:
x = 37/6