Odpowiedź:
x = 5 v x = 7
Szczegółowe wyjaśnienie:
1) Sposób:
(x - 5)(x - 7) = 0
x - 5 = 0
x = 5
x - 7 = 0
x = 7
2) Sposób:
(x - 5)(x - 7) = 0
x² - 7x - 5x + 35 = 0
x² - 12x + 35 = 0
a = 1 , b = -12 , c= 35
∆ = b² - 4 * a *c
∆ = (-12)² - 4 * 1 * 35 = 144 - 140 = 4
√∆ = √4 = 2
x1 = (-b -√∆)/2a
x1 = (12 - 2)/2 = 10/2 = 5
x2 = (-b +√∆)/2a
x2 = (12 +2)/2 = 14/2 = 7
