解方程~~

20=75y
y=20/75
y=4/15

y = 4/15

20=75y
20/75=y
y=4/15


y=0.2666666666...(4/15)

y=20/75

20=75y
20/75=(75y)/75
y=4/15

How to solve an equation?
We know that, if a=b,
a+c=b+c
a-c=b-c
c-a=c-b
ac=bc
a/c=b/c
c/a=c/b

We can "transpose" the term at the side with the unknown to the other side.

e.g.
a+unknown=b
a+unknown-a=b-a............................we can delete the "a" at the left hand side.
unknown=b-a

Also, if the equation is with bracket(s) or fractions inside, we should cancel the denominator(s) first.
[Suppose f is the LCM of b and d. f/b=g and f/d=h]
a/b=c/d
(a/b)f=(c/d)f
ag=ch

After canelling the denominators (if the equation is with fraction(s)), we can remove the brackets (if the equation is with bracket(s)).

(a+b)c=d
ac+bc=d

Example:

(3+4+5+6+7+8+a)(1/3)=(1/6)80
(3+4+5+6+7+8+a)(2)=(1)80...............canel the denominators
2(33+a)=80......................................simpfy the equation
66+2a=80........................................remove the bracket
2a=80-66.........................................transpose the constant term
2a=14
a=14/2............................................transpose the constant term
a=7

2007-12-30 21:01:26 補充：
Please shoose me! .

　　　　20＝75y
　20除７５＝７５ｙ除７５
２０除７５＝ｙ
２０／７５＝ｙ
　４／１５＝ｙ
　　　　ｙ＝４／１５

＞＜Ａｎｓｗｅｒ　ｉｓ　４／１５（四ｏｖｅｒ十五）Ｈｏｐｅ　ｃａｎ　ｈｅｌｐ　ｙｏｕ！！！～＞ｖ＜

20=75y
y=20/75
y=4/15

20=75y
y=20/75
=4/15

問題 解方程~~
20=75y

y=0.266666

2007-12-27 20:59:51 補充：
or:20/75 4/15

y=4over15
4 up and 15 down...

2007-12-27 20:55:54 補充：
pls chose me~~~pls@@

2007-12-27 20:57:11 補充：
20=75yy=20over75 (20/15)y=4over15(4/15)