ShirokovP

Verified answer

A)
x^2 - 5x = 0 
x (x - 5) = 0

1) x = 0 ;
2) x - 5 = 0 ==> x = 5;

b) x^2 - 25 = 0 
x^2 = 25
x = ± √25
x = ±  5

c) x^2 + 9 = 0 
x^2 = - 9
Нет действительных корней