Răspuns:
Explicație pas cu pas:
Se fac cu Delta (Δ)
a) [tex]x^{2} +4x-5=0[/tex]
Rezolvare:
Δ=[tex]b^{2}-4ac[/tex]
Δ=[tex]4^{2}-4[/tex]×1×(-5)
= 16+20
=36
x1 [tex]\frac{-b+/-\sqrt{delta} }{2a}[/tex]
x1=-4+[tex]\sqrt{36}[/tex]/2 x2=-4-[tex]\sqrt{36}[/tex]/2
x1=-4+6/2 x2=-4-6/2
x1=2/2=1 x2=-10/2=-5
in acelasi model se face si la b), daca ai nevoie de ajutor, imi zici
b) [tex]2x^{2} -3x-2=0[/tex]
Δ=[tex]b^{2}-4ac[/tex]
Δ=[tex](-3)^{2} - 4[/tex]×2×(-2)
=9+16
=25
x1,2= [tex]\frac{-b+/-\sqrt{delta} }{2a}[/tex]
x1=-(-3)+[tex]\sqrt{25}[/tex]/4
x1= 3+5/4 x2=3-5/4
x1=8/4=2 x2=-2/4=-1/2
