(1)兩邊同是乘以7得： 2x+11=21-10.5x
12.5x=10
x=0.8
(2)化簡(jiǎn)方程（45/100)x+9/100(426-x)=426*(15/100)
(45/100)x+(9*426)/100-(9/100)x=(426*15)/100
(45/100)x-(9/100)x=(426*15)/100-(9*426)/100
(36/100)x=(6*426)/100
x=71
應(yīng)用題：
(1)應(yīng)該有x人生產(chǎn)方桌,22-x人生產(chǎn)方凳
x*12=(22-x)*18/4
8x=66-3x
11x=66
x=6
應(yīng)該有9人生產(chǎn)方桌,16人生產(chǎn)方凳.
（2）設(shè)甲、乙兩地路程為S
則有：
[S-(40km/h)*3h]/30km/h+3h=S/40km/h+45min
S/30km/h-4h+3h=S/40km/h+3/4h
S=(7/4)*120km
S=210km
甲、乙兩地路程為210km