Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

Really basic question, I just can't get it.

I have $yt - y = 2t$. I want to solve it in terms of $t$ rather than $y$. The answer is $t = \frac{y}{y-2}$.

How do I isolate the $t$ on one side and the $y$'s on the other? I considered factoring the left-hand side into $y(t - 1)$, but i couldn't get anywhere with it. I suppose I could subtract $yt$ from both sides, then try again. Any help?

share|improve this question
    
You want to "isolate" $t$, so you want to bring all the $t$ stuff to one side. –  André Nicolas Feb 4 '13 at 5:48

1 Answer 1

up vote 3 down vote accepted

We proceed as follows: $$\begin{align*} yt-y&=2t\\ yt&=y+2t\\ yt-2t&=y\\ t(y-2)&=y\\ t&=\tfrac{y}{y-2} \end{align*}$$ We should be careful to note that this answer is correct only when $y\neq 2$; otherwise we would be dividing by zero.

share|improve this answer
    
Thanks very much - I was trying to factor then add inverses, I had the process backwards. Cheers! –  Peter Feb 4 '13 at 5:57
    
Glad I could help! –  Zev Chonoles Feb 4 '13 at 6:04

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.