Раскроем скобки:
(5x + 1)(5x - 1) - (5x + 1)^2 = 0
25x^2 - 5x + 5x - 1 - (25x^2 + 10x + 1) = 0
Упростим:
25x^2 - 1 - 25x^2 - 10x - 1 = 0
-10x - 2 = 0
-10x = 2
x = -2/10
x = -1/5
Ответ: x = -1/5.
Раскроем скобки:
(5x + 1)(5x - 1) - (5x + 1)^2 = 0
25x^2 - 5x + 5x - 1 - (25x^2 + 10x + 1) = 0
Упростим:
25x^2 - 1 - 25x^2 - 10x - 1 = 0
-10x - 2 = 0
-10x = 2
x = -2/10
x = -1/5
Ответ: x = -1/5.