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  • Utilisateur Brainly
2014-09-20T22:13:50+02:00
7(3x + 5) = 3(3 - 2x) + 2(5x - 21) 
21x + 35 = 9 - 6x + 10x - 42
21x + 6x - 10x = 9 - 42 - 35
17x = - 68
x = - 68/17
x = - 4
2014-09-20T22:45:44+02:00

Bonsoir

7(3x + 5) = 3(3 - 2x) + 2(5x - 21) 
21x + 35 = (9 - 6x )+ (10x - 42)
21x + 6x - 10x = 9 - 42 - 35
17x = - 68
x = -68/17
x = -4