Sagot :
B= (x+2)^2-(1-2x)^2
= (x+2-(1-2x)) fois (x+2+(1-2x))
=(x+2-1+2x)(x+2+1-2x)
=(3x+1)(-x+3)
C= 4-16^2+(4x+2)(5x-4)
=4-16x^2+20x^2-16x+10x-8
=-4+4x^2-6x
=4x^2-6x-4
= 2(2x^2-3x-2)
=2(x(2x+1)-2(2x+1)
=2(2x+1)(x-2)
= (x+2-(1-2x)) fois (x+2+(1-2x))
=(x+2-1+2x)(x+2+1-2x)
=(3x+1)(-x+3)
C= 4-16^2+(4x+2)(5x-4)
=4-16x^2+20x^2-16x+10x-8
=-4+4x^2-6x
=4x^2-6x-4
= 2(2x^2-3x-2)
=2(x(2x+1)-2(2x+1)
=2(2x+1)(x-2)