Réponses

2013-01-19T09:39:01+01:00

Bonjour

a)

2y-(4+3y) = 7-(-3-5y)+4y

2y - 4 - 3y = 7 + 3 + 5y + 4y

10y = -14

y = -14/10 = -7/5 

b) 

7/2y - 5/3 = 13/2

7/2y = 13/2 + 5/3

y = 36/6 * 2/7 

y = 12/7

c)

4y² =100

y² = 100/4

y = V100 / V4    ( V veut dire racine de ) 

y = 10 / 2 = 5

d)

(2y-1)² = 49     on voit deux carrés 

2y-1 = 7 

2y = 8

y = 4