mathematics 數學

3x+10/2x+25=30
3x+5/x=5
2x(3x+5/x)=10x
6x^2+10=10x
6x^2=10(x-1)
3x^2=5(x-1)
x沒解
(3x+10)/(2x+25)=30
3x+10=60x+750
-57x=740
x=-13.0,cor to 3 sig fig

I am a bit confused with your question.
I suppose it is either one of the following:


Question 1
========

First of all, 3x + 5/x = 5

Multiply each term by x.

3x^2 + 5 = 5x

3x^2 - 5x + 5 = 0

It has no solution for the discriminant is smaller than 0.

Question 2
========

( 3x + 10 ) / ( 2x + 25 ) = 30
30( 2x + 25 ) = 3x + 30
60x + 750 = 3x + 30
57x = -720
x = -720/57


2010-11-27 22:03:12 補充：
A mistake was made in my Question 2
The correct one is

( 3x + 10 ) / ( 2x + 25 ) = 30
30( 2x + 25 ) = 3x + 10
60x + 750 = 3x + 10
57x = -740
x = -740/57

請問10/2x係10/2 x定2x分之10?

如果係10/2 x.
3x+10/2x+25=30
3x+10/2x=5
8x=5
x=5/8

如果係2x分之10.
3x+10/2x+25=30
3x+10/2x=5
2x(3x+10/2x)=2x(5)
6x+10=10x
10=10x-6x
4x=10
x=2.5

2010-11-27 20:31:10 補充：
如果係10/2 x.
可以1開始寫成5x

2010-11-27 20:43:05 補充：
原來係咁(汗-_-'')
(3x+10)/(2x+25)=30
3x+10=30(2x+25)
3x+10=60x+750
3x-60x=750-10
-57x=740
x=-740/57