# Solve this equation: (x + 4)(x - 4) = 9

**Solution:**

Given equation is

(x + 4)(x - 4) = 9

We know (a + b)(a - b) = a^{2} - b^{2}, is the difference of squares.

Therefore

(x + 4)(x - 4) = x^{2} - 16

Hence,

x^{2} - 16 = 9

x^{2} = 16 + 9

x^{2} = 25

x = ± 5

## Solve this equation: (x + 4)(x - 4) = 9

**Summary:**

On solving this equation (x + 4)(x - 4) = 9 we obtain x = ± 5.

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