(x+1)(x+2)=56
[tex] x^{2} [/tex]+2x+x+2=56
[tex] x^{2} [/tex]+3x-54=0
Δ=[tex] b^{2} [/tex]-4ac
Δ=9+216
Δ=225
[tex] x_{1}, x_{2} [/tex]=[tex] \frac{-b \frac{+} \ \sqrt{delta} }{2a} [/tex]
=[tex] \frac{-3 \frac{+}. \sqrt{225} }{2} [/tex]⇒x1=[tex] \frac{-3+15}{2}[/tex]=[tex] \frac{12}{2} [/tex]=6
⇒x2=[tex] \frac{-3-15}{2} [/tex]=[tex] \frac{-18}{2} [/tex]=-9
S-(x1, x2)={6, -9}
