1)... x² + 5x + 6 = x²+2x+3x+6=x(x+2)+3(x+2)=(x+2)(x+3) ;
... = x(x²-4x+4)=x(x-2)² ;
2)... 5x-3 ≤ -24+6x ⇔ 24-3 ≤ 6x-5x ⇔ 21 ≤ x ⇒ x ∈ [21 ; [tex]+\infty[/tex]) ;
3)... [tex]A_{dreptunghi}=L\cdot{l}=12\,\cdot\frac{2}{\not3}\cdot\not{12}_4=12*2*4=96[/tex]
