唔識做數呀!! F.2既數..

1) y = 2/3x + 1/x
3y = 2x + 3x
3y = 5x
x = 3/5y

2) y = 1/5x - 1/x
5y = x - 5x
5y = -4x
x = -5/4y

3) y = 1/2x - 1/5x
10y = 5x - 2x
10y = 3x
x = 10/3y

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

5) y = (x+2)/(2-x)
2y -xy = x + 2
2y - 2 = x + xy
2y - 2 = x(1 + y)
x = (2y - 2)/(1 + y)

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

1. y = 2/3x + 1/x
y = 2/3x + 3/3x
y = 5/3x
x = 5/3y ..

2. y = 1/5x - 1/x
y = 1/5x - 5/5x
x = - 4/5y ..

3. y= 1/2x - 1/5x



.......( 之後個d 都係咁做...)