Bonsoir,
(x+8)(x+2)+x+2 = (x+8)(x+2)+1(x+2) = (x+2)(x+8+1) = (x+2)(x+9)
(x+2)²+(x+2)(4x-9) = (x+2)(x+2)+(x+2)(4x-9) = (x+2)(x+2+4x-9) = (x+2)(5x-7)
(x+2)(x-2)+(2x-6)(3x+6) = (x+2)(x-2)+(2x-6)3(x+2)
= (x+2)(x-2+2x-6+3)
= (x+2)(3x-5)
(x+2)²+x²-4 = (x+2)²+x²-2² = (x+2)(x+2)+(x+2)(x-2)
= (x+2)(x+2+x-2)
= 2x(x+2)
x² + 4x + 4 = (x+2)²