Răspuns:
Explicație pas cu pas:
2
x²-5x-14=(x-7)(x+2)
x²-5x=x(x-5)
x²+25=0 nu are solutii in R
3
3x²-x+1=0
x1,2=1±√1-12/6 Δ<0 ecuatia nu are solutii in R
3x²-x-2=0
x1,2=1±√1+24/6=1±5/6 x1=6/6=1 x2=-4/6=-2/3
3x²-x-2=(x-1)(3x+2)
4
x²-4x+4≤0 fiind patrat perfect e valabila numai x²-4x+4=0
(x-2)²=0 ⇒x=2
