a) 4x² - 8x = 0
4x*x - 4x*2 = 0
4x(x-2) = 0
4x = 0 v x-2 = 0
x=0 x = 2
b) 2x² - 10x = 0
2x*x - 2x*5 = 0
2x(x-5) = 0
2x = 0 v x-5 = 0
x = 0 x = 5
c) x(x-7) = 0
x = 0 v x-7 = 0
x = 7
d) 25 - x² = 0
5² - x² = 0
(5 - x)(5 + x) = 0
5-x = 0 v 5+x = 0
x = 5 x = -5
Pozdrawiam :)
