<趕`後日交`40 marks> 各位知識朋友 , 入黎幫我手 ar !!! ( 數學F.2 ) (4)

(a)
y=(2x)/(x-2)
y(x-2)=2x <-----先乘分母(x-2)過去, 消除分數
yx-2y=2x <-----將y乘入去, 方便之後將個x一齊抽出
7x-2x=2y <-----將有x的野調去一邊, 冇x的野調晒去另一邊
x(y-2)=2y <----求先將y乘入去就係咁解la, 就係依家可以一齊抽x
x=(2y)/(y-2) <----將成舊異物(y-2)除過去, 搞掂

(b)
y=(x+2)/(2-x) <-----steps同上
y(2-x)=x+2
2y-yx=x+2
2y-2=x+yx
2y-2=x(1+y)
(2y-2)/(1+y)=x
x=(2y-2)/(1+y)

(c)
y=(3x+1)/(x-1)<-----steps同上
y(x-1)=3x+1
yx-y=3x+1
yx-3x=1+y
x(y-3)=1+y
x=(1+y)/(y-3)

(a)

y=2x/x-2

y(x-2) =2x

y(x-2)=2x

x=[y(x-2)]/2

(or)...

x=(xy/2)-(2/2)

x=(xy/2))-1

(b)

y=x+2/2-x

y(2-x)=x+2

2y-xy=x+2

2y-2=x-xy

x(1-y)=2(y-1)

x=2(y-1)/(1-y)

(c)

y=3x+1/x-1

y(x-1)=3x+1

xy-y=3x+1

xy-3x=1+y

x(y-3)=1+y

x=(1+y)/(y-3)

2008-10-11 23:49:11 補充：
(a) is wrong!!


y=2x/x-2

y(x-2) =2x

xy-2y=2x

xy-2x=2y

x(y-2)=2y

x=2y/(y-2)

(or)...

x=(2y/y)-(2y/2)

x=2-y

2008-10-11 23:56:13 補充：
CHOOSE ME LA!!!!!

咁你應該知系要求x等如咩架la

(a)

y=2x/x-2

y(x-2) =2x/x-2(x-2)

y(x-2)=2x

x=y(x-2)/2

(b)

y=x+2/2-x

y(2-x)=x+2

x=y(2-x)-2

(c)

y=3x+1/x-1

y(x-1)=3x+1

y(x-1)-1=3x

x=[y(x-1)-1]/3