Solve the following equation:

x(2x + 5) = 25

Given, x(2x + 5) = 25.

⇒ 2x² + 5x - 25 = 0

⇒ 2x² + 10x - 5x - 25 = 0

⇒ 2x(x + 5) - 5(x + 5) = 0

⇒ (x + 5)(2x - 5) = 0

⇒ x + 5 = 0 or 2x - 5 = 0

⇒ x = -5 or 2x = 5

⇒ x = -5 or x = $\dfrac{5}{2}$.

Hence, roots of the given equations are -5, $\dfrac{5}{2}$.