Grade 9 Equations with Fractions

Nay

New member
Joined
Jun 11, 2012
Messages
1
Hi all.
I have an ext. exam coming up tomorrow and I needed help with Equations with Fractions.
I looked up a tutorial and got this, which I do not understand:

x
3
+x − 2
5
= 6

Multiply both sides of the equation -- every term -- by the LCMof denominators. Every denominator will thencancel. We will then have an equation without fractions.

The LCM of 3 and 5 is 15. Therefore, multiply every term on both sides by 15:
15·x
3
+15·x − 2
5
= 15· 6

Each denominator will now cancel into 15 -- that is the point
excl.gif
-- and we have the following simple equation that has been "cleared" of fractions:

5x + 3(x − 2)=90.




How do they multiply the terms by 15?
Like how do they multiply 15 by x over 3?
This is confusing. :p

Thanks in advance!
smile.png
 
Hi all.
I have an ext. exam coming up tomorrow and I needed help with Equations with Fractions.
I looked up a tutorial and got this, which I do not understand:

x
3
+
x − 2
5
= 6

Multiply both sides of the equation -- every term -- by the LCMof denominators. Every denominator will thencancel. We will then have an equation without fractions.

The LCM of 3 and 5 is 15. Therefore, multiply every term on both sides by 15:
15·
x
3
+
15·
x − 2
5
= 15· 6

Each denominator will now cancel into 15 -- that is the point
excl.gif
-- and we have the following simple equation that has been "cleared" of fractions:

5x + 3(x − 2)
=
90.




How do they multiply the terms by 15?
Like how do they multiply 15 by x over 3?
This is confusing. :p

Thanks in advance!
smile.png

Can you find:

15 * \(\displaystyle \dfrac{7}{3}\) = ???

In your posted problem you have 'x' instead of '7' (in my example). Treat the same way!

If you need to brush up on "fraction multiplication" - do a google search - you'll find many sites with lots of examples.
 
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