Bonsoir,
la propriété de distrivité de la multiplication donne :
( a + b ) ( x + y ) = ax + ay + bx + by
( a - b ) ( x - y ) = ax - ay + ax + by
Donc
D = ( 11y-8 ) ( 1-2y ) = 11y×1 + [ 11y×(-2y) ] + [ (-8)×1 ] + [(-8)×(-2y) ]
= 11y -22y^2 -8 +16y
= -22y^2 + 27y - 8
E = 18b^2 + 81b + 4b + 18 = 18b^2 + 85b + 18
F = -15x^3 - 40x^2
G = -42ab + 70a - 6b + 10
H = -5x^3 + 15x^2 - x^2 +3x = -5x^3 + 14x^2 + 3x
I = 4x^4 + 22x^3 - 40 x^2 - 30x^2 - 165x + 300 = 4x^4 + 22x^3 - 70x^2 - 165x + 300
Bonne soirée
