Developper et reduire : 1. 3(x+1)carré - (2x+2)carré 2. 3(2x)(3x-4) 3. (X+2)cube

1) 3(x^2+2x+1)-(2x^2+8x+4)
3x^2+6x+3-2x^2-8x-4
X^2-2x-1

Le signe ^ étant puissance de...

2) 6x(3x-4)
18x^2-24x

3) x^2+4x+4

1.  3(x+1)² - (2x+2)²
= 3(x²+2x+1) - (4x²+4x+4)
= 3x²+6x+3-4x²-4x-4
= -x²+2x-1
     Δ = b²-4ac = 4-4*(-1)*(-1) = 0
     x = -b/(2a) = -2/(2*(-1)) = 1
= -(x-1)²

2. 3(2x)(3x-4)
= 6x(3x-4)
= 18x²-24x

3. (X+2)^3
= (x+2)(x+2)(x+2)
= (x²+4x+4)(x+2)
= x^3+4x²+4x+2x²+8x+8
= x^3+6x²+12x+8