帮我解方程94.5-2x=6又1/2x+54.537又3/8-2又1/2x=4又1/2+21又3/84（x+5）=9x+

94.5-2x=6又1/2x+54.5
6.5x+2x=94.5-54.5
8.5x=40
x=40÷8.5
x=4又12/17
37又3/8-2又1/2x=4又1/2+21又3/8
2.5x=37.375-4.5-21.375
2.5x=11.5
x=11.5÷2.5
x=4.6
4（x+5）=9x+12.5
4x+20=9x+12.5
5x=7.5
x=1.5
0.9（x-3）-0.8x=2
0.9x-2.7-0.8x=2
0.1x=4.7
x=47
（3/4）*（84-x）=1/2x+18
252-3x=2x+36
5x=216
x=4.32
（x+4）/（0.4）=18
x+4=18*0.4=7.2
x=3.2
(13-x)/(21-x)=8/13
8(21-x)=13(13-x)
168-8x=169-13x
5x=1
x=1/5
（4又1/2x-3）/（3x-1）=1/2
2(4.5x-3)=3x-1
9x-6=3x-1
6x=5
x=5/6