# Transposing question

• Jun 17th 2011, 02:16 PM
joebard
Transposing question
(New here, hope I'm posting in the right forum...)

Hello! I am working on a set of 30 problems to do with transposing equations. I have been doing well up until now, but I have hit this at question 28:

y = (a + x) / (5 - bx) rearranged for x

I know that the answer should be:

x = (5y - a) / (1 + by)

My working so far is:

y(5 - bx) = a + x

5y - ybx = a + x

...and now I get stuck. I can't seem to isolate x. I see that both the question and answer are equal but I don't see how they got there (also confused where the constant "1" came from). Any help with this would be greatly appreciated!
• Jun 17th 2011, 02:22 PM
pickslides
Re: Transposing question
Looks good so far

\$\displaystyle 5y - ybx = a + x\$

Now put the x's on the same side.

\$\displaystyle 5y -a= x+ybx\$

Factor out x.

\$\displaystyle 5y -a= x(1+yb)\$

Finish him off.
• Jun 19th 2011, 11:38 AM
joebard
Re: Transposing question
Ah thank you very much. My knowledge of factoring was lacking and I didn't see I could do it there. Sorted!