Réponse :
B= (2x+3)(x+2)
= 2x X x+ 3 X x + 3 X 2 + 2x X 2
=2x² + 4x + 3x + 6
=2x² + 7x + 6
C= (3x-1)(4+x)
= 3x X 4 + 3x X x -1 X 4 - 1 X x
= 12x + 3x² - 4 - x
= 11x + 3x² -4
A= (x+2)(x+5)
=x X x + x X 5 + 2 X x + 2 X 5
= x² + 5x + 2x + 10
= x² + 7x + 10
E= (2x-3)(6x-5)
= 2x X 6x - 2x X 5 - 3 X 6x + 3 X 5
= 12x² - 10x - 18x + 15
= 12x² - 28x + 15
F= 6(x - 2) + (x + 1)(2x + 5)
= 6 X x - 6 X 2 + x X 2x + x X 5 + 1 X 2x + 1 X 5
= 6x - 12 + 2x² + 5x + 2x + 5
= 13x - 7 + 2x²
D= (2x + 1)(4 - 3x)
= 2x X 4 - 2x X 3x + 1 X 4 - 1 X 3x
= 8x - 6x² + 4 - 3x
= 5x - 6x² + 4
Explications étape par étape :
