Răspuns:
Explicație pas cu pas:
a) 2x²+x-3=0
x1,2=-1±√1+24/4=-1±5/4 x1=-1-5/4=-3/2 x2=-1+5/4=1 ∈R sunt solutii
b) 3x²+2x-5=0
x1,2=-1±√1+15/6 x1=-1-4/6=-5/6 x2=3/6=1/2 x∈N⇒ecuatia Nu admite solutii nr naturale
c) (x+1+x-2)(x+1-x+2)=1 (2x-1)×3=1 6x-3=1 6x=4 x=2/3 dar x∉Z
