7x^2 - 4 = 0
7x^2 = 4
4
x^2 = / : V
7
x = V4/7
x = - 2/V7 i x = 2V7
проверим, верно ли
7 *(2V7)^2 - 4 = 0
7 * - 4 = 0
верно
7x^2 - 4 = 0
7x^2 = 4
4
x^2 = / : V
7
x = V4/7
x = - 2/V7 i x = 2V7
проверим, верно ли
7 *(2V7)^2 - 4 = 0
4
7 * - 4 = 0
7
верно