Simple formula rearrange

dennyloi

New member
Joined
Jan 4, 2014
Messages
8
I have a formula that I want to simplify as follows:

(a/x) + (a/y-x)

someone told me that it simplifies to: ax / x(y-x).

If this is right, can someone help me fill in the intermediate steps?

Thanks
Denny
 
I have a formula that I want to simplify as follows:

(a/x) + (a/y-x)

someone told me that it simplifies to: ax / x(y-x).

If this is right, can someone help me fill in the intermediate steps?

Thanks
Denny

If the problem is \(\displaystyle \ \ \dfrac{a}{x} \ + \ \dfrac{a}{y - x}, \ \ \) then you need grouping symbols around the second denominator.

Also, that someone is wrong who told you it simplifies to that expression. And that expression is missing
grouping symbols in its denominator anyway.


"a/x + a/(y - x)" is a correct form.


What is your least common denominator of the two fractions? I can't stay with you at this time.
 
Last edited:
If the problem is \(\displaystyle \ \ \dfrac{a}{x} \ + \ \dfrac{a}{y - x}, \ \ \) then you need grouping symbols around the second denominator.

Also, that someone is wrong who told you it simplifies to that expression. And that expression is missing
grouping symbols in its denominator anyway.


"a/x + a/(y - x)" is a correct form.


What is your least common denominator of the two fractions?

I tried it substituting in numbers. Eg:

a = 10, y = 3, x = 2.

a/x + a/(y - x) -> (10/2) + (10/3-2) -> 5 + 10 = 15

ax / x(y-x) -> (10*2) / (2(3-2)) -> 20 / 2 = 15

Maybe I have written the original equation wrong...?
 
The typo is probably in above; should be ay / (x(y-x))


You are right, it should be ay / (x(y-x))

My question still remains however, how can we combine the 2 equations to get ay / (x(y-x)) ?

Thanks
 
I have a formula that I want to simplify as follows:

(a/x) + (a/y-x)

someone told me that it simplifies to: ax / x(y-x).

If this is right, can someone help me fill in the intermediate steps?

Thanks
Denny
You'll do these exactly the same way you'll solve \(\displaystyle \frac{2}{5} + \frac{3}{7} = ??\)

\(\displaystyle \frac{2}{5} + \frac{3}{7} = ??\)

LCM of the denominators (= 5*7 = 35) -

you will convert all the denominators to 35 by suitable multiplication and division

\(\displaystyle = \ \dfrac{2}{5}*\dfrac{7}{7} \ + \ \dfrac{3}{7}*\dfrac{5}{5} \)

\(\displaystyle = \ \dfrac{14}{35} \ + \ \dfrac{15}{35} \)

\(\displaystyle = \ \dfrac{14 + 15}{35} \)

\(\displaystyle = \ \dfrac{29}{35} \) ............. done

Follow the exact same steps.

If you still have problem write back - showing your work.
 
Did your math teacher not show how?

He probably did, but that was probably about 20 years ago now, and when you don't use it, you lose it.

Anyway, It followed the answer above and got the solution.

Thanks
 
Top