Răspuns:
Explicație pas cu pas:
1) x²-2x-6=0
x1,2=(1±√1+6) ⇒x1=1+√7 si x2=1-√7
x²-2x-6=(x-1-√7)(x-1+√7
3. 5m²-2m-16=0
m1,2=(1±√1+5·16)/5=(1±√81)/5=(1±9/)5 ⇒
m1=10/5=2 si m2=-8/5
5m²-2m-16=(x-2)(5m+8)
4. 8y²-7y+2=0
x1,2=(7±√49-64)/16 ⇒Δ negativa nu are solutii reale
5. 11y²+4y-2=0
x1,2=(-2±√4+22)/11=(-2±√26)/11=
x1=(√26-2)/11 si x2=-(√26+2)/11
6. 16x²+5x-19=0
x1,2=(-5±√25+4·16·19)/32=(-5±√1241)/32
x1≈(-5+35)/32=30/32=15/16 x2≈(-5-35)/32=-40/32=-5/8
7. 20z²-18z-16=0
z1,2=(9±√81+20·16)/20=(9±√401)/20
z1≈(9+20)/20=29/20 2≈(9-20)/20=-11/20
8. 15x²+17x-5=0
x1,2=(-17±√289+20·15)/4·15=(-17±√589)/60
