Bonjour pouvez m’aider Exercices 21 a 31, resoudre chaque équation. 27 a. 9 - 2a =-3 b. 4t + 3 = -2t 28 a. 5x + 3 = 0 b. 0= -7y +5 29 a. 2y + 9 = 4 – 3y b. -2x

27a

-2a=-3-9 = -12

-a= -6

a=-6

27b

3=-2t-(-4t)

3=-6t

t=-3/6

28a

5x=-3

x=-3/5

28b

-7y=-5

-y=7/5

y=-7/5

29a

2y + 3y = 4-9

5y = -5

y=-1

29b

-2x + x = 2+5

-x = 7

x = 7

30a

2x-3x = -7-1

-x= -8

x = 8

30b

7t + 4t = 14 - 22

11t = -8

t = -8/11

31a

0.7m + 1.8m = -10

2.5m = -10

m = -10/2.5 = -4

31b

-y - 2y = -7.4 + 3.8

-3y = -3.6

-y = -3.6/3

y = 3.6/3 = 1.2