a)x³+2x²-9x-18=0
x² * (x+2) - 9 * (x+2) = 0
(x² - 9) * (x+2) = 0
(x+3) * (x-3) * (x+2) = 0
x = -3 lub x = 3 lub x = -2
b)x³+4x²-5x=0
x * (x²+4x - 5) = 0
x * (x + 5) * (x - 1) = 0
x = 0 lub x = -5 lub x = 1
c)x⁴-10x²+9=0
(x² - 9) * (x² - 1) = 0
(x+3) * (x - 3) * (x-1) * (x+1) = 0
x = -3 lub x = 3 lub x = 1 lub x = -1
