F.4 maths questions

(2x-5) = (x-3) (2x-5)
2x-5=2x^2-11x+15
2x^2-13x+20=0
(2x-5)(x-4)=0
x=4 or x=2.5

3x - 8x + 4 = 0
-5x+4=0
-5x=-4
x=-4/-5
x=4/5(0.8)

2008-10-06 02:39:45 補充：
樓上第一題錯在將 2x-5 除 2x-5，排除了2x-5=0既可能性

1.(2x-5) = (x-3) (2x-5)
(2x-5)/(2x-5)=(x-3)
1=x-3
x=-3

2. 3x - 8x + 4 = 0
-5x+4=0
-5x=-4
x=-4/-5
x=4/5(0.2)