Răspuns:
(3x+5)^2-(x+1)^2
=[3x+5-(x+1)]•[3x+5+(x+1)]
=(3x+5-x-1)•(3x+5+x+1)
=(2x+4)•(4x+6)
=2(x+2)•2(2x+3)
=2×2(x+2)•(2x+3)
=4(x+2)•(2x+3)
Explicație pas cu pas:
Folosim formula:a^2-b^2=(a-b)(a+b)
