1)
(7x-42)/4=(5x+5)/3-3x-6 /*12
3*(7x-42)=4*(5x+5)-(3x-6)*12
21x-126=20x+20-36x-72
21x-126=-16x-52
21x+16x=-52+126
37x=74
x=74:37
x=2
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(3x-24)/5+(7x+35)/6=(28x+6)/15+1/3 /*30
6*(3x-24)+5*(7x+35)=2*(28x+6)+10*1
18x-144+35x+175=56x+12+10
53x+31=56x+22
56x-53x=31-22
3x=9
x=9:3
x=3
=======================
(6x+15)/8-(10x+14)/3=(7x-105)/4-6 7/8 /*24
3*(6x+15)-8*(10x+14)=6*(7x-105)-24*6 7/8
18x+45-80x-112=42x-630-165
-62x-67=42x-795
42x+62x=-67+795
104x=728
x=728:104
x=7
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