Sagot :
Réponse :
Explications étape par étape
19. A = 9 ( - 3 + y ) = - 27 + 9y
B = - 6 ( 2x - 7 ) = - 12x + 42
C = 8 ( 3t + 2 ) = 24t + 16
D = - 8 ( 9 - 7x ) = - 72 + 56x
E = - 8z ( 4 - 3z ) = - 32z + 24z²
F = 3y ( - 4 + 6y ) = - 12y + 18y²
20. A = x ( x + 4 ) = x² + 4x
B = 7y ( 2 - 9y ) = 14y - 63y²
C = - 2y ( 5 - y ) = - 10y + 2y²
D = 4t ( 9 - 3t ) = 36t - 12t²
21. A = 11 + 2 ( x - 6 ) = 11 + 2x - 12 = 2x - 1
B = - 3 ( 2y - 4 ) - 2y = - 6y + 12 - 2y = - 8y + 12
C = 7 - 4 ( 8 - 2a ) + a = 7 - 32 + 8a + a = 9a - 25
D = - 15 - 9 ( - 5 + 3b ) = - 15 + 45 - 27b = - 27b + 30
E = - 5 ( 6 - 3z ) - 9 + z = - 30 + 15z - 9 + z = 16z - 39
F = 12x - 4 ( 6 - 3x ) = 12x - 24 + 12x = 24x - 24
Explications étape par étape:
20)
A= x. (x+4)
= x²+4x
B= 7y(2-9y)
= 14y. -63y²
C= -2y. (5-y)
= -10y+ 2y²
D= (9-3t)*4t
= 36t-12t²
21)
A= 11+(2x-6)
= 11+2x-6
= 5+2x
B= -3(2y-4)-2y
= -6y+12-2y
= -8y+12
C= 7-4(8-2a)+a
= 7-32+8a+a
= 25+9a
D= -15-9(-5+3b)
= -15 +45-27b
= 30-27b
E= -5(6-3t)-9+z
= -30+15t-9+z
= -39+15t+z
F= 12x-4(6-3x)
= 12x-24+12x
= 24x-24
voila