# How do you use the difference of two squares formula to solve 4x^2=25?

$f \left(x\right) = 4 {x}^{2} - 25 = \left(2 x - 5\right) \left(2 x + 5\right) = 0$
$\left(2 x - 5\right) = 0 - \to x = \frac{5}{2}$
$\left(2 x + 5\right) = 0 - \to x = - \frac{5}{2}$