Répondre :
E = 4x(x+3 )
F = x²+6x+9
a) développer E
E = 4x(x+3 )
=4x²+12x
b) réduire E - F
=4x²+12x-(x²+6x+9)
=4x²+12x-x²-6x-9
=3x²+6x-9
c) factoriser E + F
4x(x+3)+x²+6x+9
=4x(x+3)+(x+3)²
=4x(x+3)+(x+3)(x+3)
=(x+3)(4x+x+3)
=(x+3)(5x+3)
F = x²+6x+9
a) développer E
E = 4x(x+3 )
=4x²+12x
b) réduire E - F
=4x²+12x-(x²+6x+9)
=4x²+12x-x²-6x-9
=3x²+6x-9
c) factoriser E + F
4x(x+3)+x²+6x+9
=4x(x+3)+(x+3)²
=4x(x+3)+(x+3)(x+3)
=(x+3)(4x+x+3)
=(x+3)(5x+3)