x^2 - 11x + 18 = 0
D = b^2 - 4ac = (-11)^2 - 4*1*18 = 121-72 = 49
VD = V49 = 7
x1 = (11+7)/2 = 18/2 = 9
x2 = (11-7)/2 = 4/2 = 2
x^2 - 4x -4 = 0
D = b^2-4ac = 4^2-4*1*(-4) = 16+16 = 32
VD = V32 = V(16*2) = 4V2
4+4V2
x1 = ----------------- = 2+2V2
2
4 - 4V2
x2 = ----------------- = 2 - 2V2
2
2x^2 - 10x = 0
x (2x-10)=0
x = 0 i 2x-10=0
2x=10
x = 10:2
x = 5