Respostas

2013-09-17T11:44:29-03:00
(2x + 5)² = (3x)² + 5²
4x² + 20x + 25 = 9x² + 25
9x² + 25 = 4x² +20x + 25
9x² - 4x² = 20x + 25 - 25
5x² = 20x        simplifica por 5x
x= 4