①2x+1=5
2x=4
x=2
②5y-2y=18
3y=18
y=6
③n+1/3=2/5
n=2/5-1/3
n=-1/15
④3/5+m=7/10
m=7/10-3/5
m=1/10
⑤x-3/4=1/12
x=1/12-3/4
x=-2/3
⑥x+4x=20
5x=20
x=4
⑦6m-3m=27
3m=27
m=9
⑧2y+y=105
3y=105
y=35
⑨2y+4y=15
6y=15
y=2.5
⑽9x-4x=6.5
5x=6.5
x=1.3
⑾8n-n=14
7n=14
n=2
⑿1/2+x=5/6
x=5/6-1/2
x=1/3
⒀x-7/10=1/5
x=1/5+7/10
x=9/10
⒁x+1/4=1/2
x=1/2-1/4
x=1/4
书上找
3X+2=4X
答案:X=2
自己找就行了