(x+1)*(x+2)=[tex] x^{2} [/tex]+3x+2
[tex] x^{2} [/tex]+3x+2-72=0 (ecuatie de gradul II)
a=1,b=3,c=-70
Δ=delta
Δ=[tex] b^{2} [/tex]-4ac
=9-(-280)
=289 (ecuatia are doua solutii reale)
x1=[tex] \frac{-b+\sqrt{delta}}{2a} [/tex]
x1=7
x2=[tex] \frac{-b-\sqrt{delta}}{2a} [/tex]
x2=-10
