Answer:
x = 6
Explanation:
Given
6x² - 2x + 36 = 5x² + 10x ( subtract 5x² + 10x from both sides )
x² - 12x + 36 = 0 ← in standard form
This is a perfect square of the form
(x - a)² = x² - 2ax + a²
36 = 6² ⇒ a = 6 and 2ax = (2 × 6)x = 12x, hence
(x - 6)² = 0
x - 6 = 0 ⇒ x = 6