BONJOUR qui peut m aider a resoudre ces equations merci a)2/7x+1/7=4 b) 4/5x+7=3/5 c)2+3(b-9)=5-(b+3) d)4-5(b-2)=b+12
Mathématiques
Anonyme
Question
BONJOUR qui peut m aider a resoudre ces equations merci
a)2/7x+1/7=4
b) 4/5x+7=3/5
c)2+3(b-9)=5-(b+3)
d)4-5(b-2)=b+12
a)2/7x+1/7=4
b) 4/5x+7=3/5
c)2+3(b-9)=5-(b+3)
d)4-5(b-2)=b+12
1 Réponse
-
1. Réponse aminerbt
a)
2/7x+1/7 = 4 ---> 2/7x = 4 - 1/7
---> 2/7x = (4*7)/7 - 1/ 7
---> 2/7x = 28-1/ 7
---> 2/7x = 27/7
---> 2*7= 27* 7x
---> 14 = 189x
---> x=14/189
b)
4/5x+7 = 3/5 ---> 4/5x = 3/5 -7
---> 4/5x = (3-35)/5
---> 4/5x = -32/5
---> 4*5 = -32*5x
--->20= - 160x
---> x = - 20/160
---> x = - 2/16
---> x = - 1/8
c)
2+3(b-9)=5-(b+3) ---> 2+3b-27=5-b-3
--->+3b+b =5-3-2+27
---> 4b = 27
---> b = 27/4
d)
4-5(b-2)=b+12 ---> 4-5b+10=b+12
---> -5b-b =12-10 -4
---> -6b =-2
---> b =(-2) / (-6)
---> b =2 / 6
---> b =1/3