(5x + 2)² - 81 = 0
(5x + 2)² - 9² = 0
(5x + 2 - 9)(5x + 2 + 9) = 0
(5x - 7)(5x + 11) = 0
Спокойной ночи ))
5/7x9 - 3/14x9 -3/2x9 = -1
10/14x9 - 3/14x9 - 21/14x9 = -1
7/14x9 - 21/14x9 =-1
-14/14x9 = -1