Solve the equation. x² + 18x + 81 = 25

Solution:

Given equation is x² + 18x + 81 = 25

The LHS of the given equation is similar to perfect square a² + 2ab + b² = (a + b)²

x² + 2(9)x + 92 = 52

Hence, we can write them as follows

(x + 9)² = 5²

Applying square root on both sides, we get

√(x + 9)² = √5²

x + 9 = ± 5

x = 5 - 9, -5 - 9

x = -4, -14

Therefore, the solutions are -4, -14.

Solve the equation. x² + 18x + 81 = 25

Summary:

By solving x² + 18x + 81 = 25 we get x = -4, -14.