Răspuns :
(4x+1)² -(2x+3)²=[(4x+1)-(2x+3)][(4x+1)+(2x+3)]=
=(4x+1-2x-3)(4x+1+2x+3)=
=(2x-2)(6x+4)=
=2(x-1)(3x+2)
=(4x+1-2x-3)(4x+1+2x+3)=
=(2x-2)(6x+4)=
=2(x-1)(3x+2)
=(4x+1+2x+3)[(4x+1)-(2x+3)=(6x+4)(4x+1-2x-3)=(6x+4)(2x-2)=2(3x+2)*2(x-1)=4(3x+2)(x-1).
am folosit formula a^2-b^2=(a+b)(a-b) unde a=4x+1, iar b=2x+3
am folosit formula a^2-b^2=(a+b)(a-b) unde a=4x+1, iar b=2x+3