form 1數

如果你覺得方程式中出現小數或分數
係呢到你可以兩邊x10

10*(2y+1)*0.2=10*(3y-2)
2(2y+1)=10(3y-2)
4y+2=30y-20
4y+2-4y=30y-20-4y
2=26y-20
2+20=26y-20+20
22=26y
(1/26)22=(1/26)26y
y=22/26=11/13

2008-06-17 18:09:27 補充：
如果你覺得方程式中出現小數或分數..覺得麻煩
可以令它變成整數

例如,兩邊*10

(2y+1)*0.2=3y-2
0.4y+0.2=3y-2
0.4y+2.2=3y
2.2=2.6y
26y=22
y=22/26=11/13

ANS=11/13

Step 1. Remove the bracket by distributive law.
(0.2)(2y) + (0.2)(1) = 3y - 2
0.4y + 0.2 = 3y - 2.
Step 2. Put all unknown items to one side of the equation and put all known items to the other side of the equation.
0.2 + 2 = 3y - 0.4y
2.2 = 2.6y
y=2.2/2.6 = 11/13.