Réponses

  • Utilisateur Brainly
2013-05-22T18:31:40+02:00

a)

3x+7=x+2

3x+7-x=x+2-x

2x+7=2

2x+7-7=2-7

2x=-5

x=-5/2

x=-2.5

 

b)

2+2y=-1+3y

2+2y-3y=-1+3y-3y

2-1y=-1

2-1y-2=-1-2

-1y=-3

y=-3/-1

y=3

 

c)

4-5a=2a-1

4-5a-2a=2a-1-2a

4-7a=-1

4-7a-4=-1-4

-7a=-5

a=-5/-7

 

d)

t-4=-3t-10

t-4+3t=-3t-10+3t

4t-4=-10

4t-4+4=-10+4

4t=-6

t=-6/4

t=-1.5