Răspuns:
Explicație pas cu pas:
x1,2=-b±√b²-4ac/2a
x²-7x+10=0 x1=2 x2=5
x²-4x+4=0 x1,2=2
x²+2x+7=0 x1,2=-1±√1-28 ecuatia nu are solutii in R Δ<0
14x²-2x=0 2x(7x-1)=0 x1=0 x2=1/7
x²+25=0 ecuatia nu are solutii in R
4x²+25=0 ecuatia nu are solutii in R