a)x*(x-1)=0
x1=0; x2=1
b)x²+2x-3=0
∆=4²-4*1*(-3)= 16+12=28
x1=-b-√∆/2a=-2-√28/2
x2=-b+√∆/2a=-2+√28/2
c)2x²-x+2=0
∆=1-4*2*2=1-16=-15<0 - nu are soluţii
