A = 8+ (a-17) = a + 8 - 17 = a - 9
B=(x-9)+x = x + x - 9 = 2x - 9
C = 2t-(5-2t) = 2t + 2t - 5 = 4t - 5
D=-(3a-2) + 3a = - 3a + 3a + 2 = 2
E=3-(9-3y) + 3y + (5+ y)-4y = 3 - 9 + 3y + 3y + 5 +y - 4y = 3y - 6
F = (5x²-3x-9)-(3x+7x²-14) = 5x² - 3x - 9 - 3x - 7x² + 14 = -2x² - 6x + 5
G=-12-(x-9)-(-7-x) = -12 -x + 9 + 7 + x = 4
H=(a-b-12) - (12− a + b) + (−b-a-12) = a - b - 12 - 12 + a - b - b - a - 12
= a - 3b - 36
pour enlever une ( ) :
+ dvt une ( ) - on recopie
- dvt une ( ) - on change les signes
Bonjour,
Calculer:
A = 8+ (a-17)= 8+a-17= a-9
B=(x-9)+x= x-9+x= 2x-9
C = 2t-(5-2t)= 2t-5+2t= 4t-5
D=-(3a-2) + 3a= -3a+2+3a= 2
E=3-(9-3y) + 3y + (5+ y)-4y= 3-9+3y+3y+5+y-4y= 3y-1
F = (5x²-3x-9)-(3x+7x²-14)= 5x²-3x-9-3x-7x²+14= -2x²-6x+5
G=-12-(x-9)-(-7-x)= -12-x+9+7+x= 4
H=(a-b-12) - (12− a + b) + (−b-a-12)= a-b-12-12+a-b-b-a-12= a-3b-36
