# not sure if it is algebra...

• Sep 13th 2010, 07:22 AM
andyboy179
not sure if it is algebra...
but im not sure how i would solve this (question in attachment!)
could someone please point me in the right direction to solving this question!?!

Attachment 18912

Thanks!!
• Sep 13th 2010, 07:36 AM
yeKciM
Quote:

Originally Posted by andyboy179
but im not sure how i would solve this (question in attachment!)
could someone please point me in the right direction to solving this question!?!

Attachment 18912

Thanks!!

$\displaystyle \frac {2x+1} {3x-7}= 2$

multiply all with 3x-7

$2x+1= 2\cdot (3x-7)$

$2x+1 = 6x-14$

$4x = 15 \Rightarrow x= 15/4$
• Sep 13th 2010, 07:40 AM
andyboy179
if i multiply all by 3x-7 it would be, 6x+7/3x-7=2? then what would i do?
• Sep 13th 2010, 07:40 AM
Sudharaka
Quote:

Originally Posted by andyboy179
but im not sure how i would solve this (question in attachment!)
could someone please point me in the right direction to solving this question!?!

Attachment 18912

Thanks!!

Dear andyboy179,

First multiply both sides of the equation by 3x-7. Afterwards you can substract 2x from both sides. Hope you can continue.
• Sep 13th 2010, 07:42 AM
andyboy179
so it would be, 6x+7/ 9x-49=2 then 4x+7/ 7x-49=2???
• Sep 13th 2010, 07:47 AM
yeKciM
Quote:

Originally Posted by andyboy179
if i multiply all by 3x-7 it would be, 6x+7/3x-7=2? then what would i do?

$\displaystyle \frac {2x+1} {3x-7}= 2 \Rightarrow
\frac {(2x+1)\cdot (3x-7)} {(3x-7) }= 2\cdot (3x-7 ) \Rightarrow 2x+1= 2\cdot (3x-7)$

so you will lose fraction after dividing $\displaystyle \frac {(2x+1)\cdot (3x-7)}{(3x-7)} = (2x+1)$

do you understand ?

P.S. when said multiply all .... means that you multiply and left and right side of equation !!!
• Sep 13th 2010, 07:50 AM
andyboy179
i really don't understand this!! could i do box method with 2x+1 and 3x-7? to get 6x^2-x-6?
• Sep 13th 2010, 08:00 AM
yeKciM
Quote:

Originally Posted by andyboy179
i really don't understand this!! could i do box method with 2x+1 and 3x-7? to get 6x^2-x-6?

let's look at this this way ...

$2x = 2 \Rightarrow x = 2/2 = 1$

multiply both sides of equation with 2 and you will have

$4x= 4 \Rightarrow x = 4/4 = 1$

do you see that nothing is changed ?

now with fractions ....

$\frac {2x}{2} = 1$

because of that under fraction is 2 (can be anything) to lose that fraction you multiply both sides with that whatever is under fraction ....

in this case multiply with 2

$\frac {2x}{2}\cdot 2 = 1 \cdot 2 \Rightarrow \frac {2x \cdot 2 }{2} = 1\cdot 2 \Rightarrow 2x = 2 \Rightarrow x =2/2 = 1$
• Sep 13th 2010, 08:07 AM
andyboy179
i kinda understand now. you say multiply both sides with 2 so how would i do 2x+1x2? and 3x-7x2?
• Sep 13th 2010, 08:12 AM
yeKciM
Quote:

Originally Posted by andyboy179
i kinda understand now. you say multiply both sides with 2 so how would i do 2x+1x2? and 3x-7x2?

you don't multiply by two in your problem there... i just do that with my example to show you that nothing changes if you multiply both sides (or add or divide or ... ) Whatever is "down" in fraction (can't figure out how to write it on English :D) you multiply both sides with THAT :D in your case it's 3x-7 :D

so you will be free of the fraction :D

P.S. when multiplying fraction with number you don't multiply down expression :D

$\displaystyle \frac {x+y}{a+b} \cdot 10 = \frac {10x +10y}{a+b}$

but only if you are multiplying fraction with fraction ...

$\displaystyle \frac {x+y}{a+b} \cdot \frac {10}{3} = \frac {10x+10y}{3a+3b}$
• Sep 13th 2010, 08:14 AM
andyboy179
OHHH so would it be 6x^2 - 10x -6?
• Sep 13th 2010, 08:20 AM
yeKciM
Quote:

Originally Posted by andyboy179
OHHH so would it be 6x^2 - 10x -6?

what would that be ... ????

lol... don't know what to do now .... probably someone who write better in English can help you :D maybe that's the problem :D

sorry...
• Sep 13th 2010, 08:22 AM
andyboy179
would the answer be 2.3?? don't worry i can understand the english but im just finding it hard to pick up how to do these sort of questions!
• Sep 13th 2010, 08:32 AM
yeKciM
Quote:

Originally Posted by andyboy179
would the answer be 2.3?? don't worry i can understand the english but im just finding it hard to pick up how to do these sort of questions!

you have solution in my first post :D (#2)

it's not problem for you with English ... it's mine :D:D:D

P.S. you need to get familiar with basic operations with fractions, and on fractions (as multiplying , divide, add , subtract .... ) so you will not have problem piking up stuff like this :D