Répondre :
f(x)=(x+2)² -3x(x+2)
=x²+4x+4-3x²-6x
=-2x²-2x+4
f(x)=(x+2)² -3x(x+2)
=(x+2)(x+2-3x)
=(x+2)(-2x+2)
=-2(x+2)(x-1)
=x²+4x+4-3x²-6x
=-2x²-2x+4
f(x)=(x+2)² -3x(x+2)
=(x+2)(x+2-3x)
=(x+2)(-2x+2)
=-2(x+2)(x-1)