这几道方程怎么解啊大X是未知数 小x是乘号1.2Xx0.9+[(2200-X)x1.15]x0.9=2331(X-15)

(1.)2X*0.9+[(2200-X)*1.15]*0.9=2331
2X*0.9+[(2200-X)*1.15*0.9]=2331
1.8X+[(2200-X)*1.035]=2331
1.8X+[2227-1.035X]=2331
1.8X+2227-1.035X=2331
1.8X-1.035X=2331-2227
2.765*x=104
X=37.61
(2).(X-15)*2-(X-15)/45=1/5
(X-15)*(2-1/45)=1/5
(X-15)*(89/45)=1/5
(X-15)=1/5*45/89
x=9/89-15=-1326/89=-14.9
(3)4%X+（290-X）*5%=13
0.4x+14.5-0.5X=13
-0.1X=-1.5
X=15
(4)5-(50-X-5)/5=2/3
15--(50-X-5)*3=2*5
15-45*3+5X=10
5X=10-15+135
X=130/5=26
(5)(2X+1) / 3-1=(10X+1)/6
(2X+1) *2-1*6=10X+1
4X+2-6=10X+1
10X-4X=2-6-1
6X=-5
X=-5/6
对于分数式可能你表达的题意没有办法看出来,不一定转化对了,但算法过程是按照我理解你给的题意做的,可能题意搞错了,下次把题写清楚哦!