1 уравнение.
x² - 9 = 0
(x - 3)(x + 3) = 0
x - 3 = 0, x + 3 = 0
x = 3, x = -3
2 уравнение.
(x - 7)(x + 7) = 0
x - 7 = 0, x + 7 = 0
x = 7, x = -7
3 уравнение.
x² - 81 = 0
(x - 9)(x + 9) = 0
x - 9 = 0, x + 9 = 0
x = 9, x = -9
1 уравнение.
x² - 9 = 0
(x - 3)(x + 3) = 0
x - 3 = 0, x + 3 = 0
x = 3, x = -3
2 уравнение.
(x - 7)(x + 7) = 0
x - 7 = 0, x + 7 = 0
x = 7, x = -7
3 уравнение.
x² - 81 = 0
(x - 9)(x + 9) = 0
x - 9 = 0, x + 9 = 0
x = 9, x = -9