Подбери корни уравнения:
а) x * x + x = 20;
б) (x − 1) * (x + 1) = 63.
x * x + x = 20
x = 4
4 * 4 + 4 = 20
16 + 4 = 20
20 = 20
(x − 1) * (x + 1) = 63
7 * 9 = 63
x − 1 = 7
x = 7 + 1
x = 8
x + 1 = 9
x = 9 − 1
x = 8
(8 − 1) * (8 + 1) = 63
7 * 9 = 63
63 = 63