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2013-10-16T18:44:26+02:00
A=60x+9x2+100=0
A = 60x +18 +100 =0
A = 60x = -118
A = x = -118/60 ou - 59/30

B=5(3x-1)=(3x-1)

15x -5 = 3x -1
15x -3x = -1 +5
12x = 4
x = 4/12 = 1/3

A = 3 -3/56 -3/24
504/168 - 9/168 - 21/168
= 504/168 - 30/168 = 484/168 = 121/42

B = 1 : (4/14 + 2/8)
= 1 : (32/112 + 28/112)
= 1 : 60/112
= 1 x 112/60 = 112/60 =  28/15
C =(3/2 -5/3) : (-3/7 +1)
= (9/6 - 10/6) : (-3/7 +7/7)
= -1/6 : 4/7
= -1/6 x 7/4
= -7/24