# Math Help - simple transposition

1. ## simple transposition

d = (r/1+rt) solving for r

I just can't seem to solve for r on this one. I know this question is pretty simple, but I'm studying on my own so I can't ask my instructor.

d = (r/1+rt)

d+rtd=r
d=r(1-td)

r = (d/1-td)

3. ## Re: simple transposition

Originally Posted by kingsolomonsgrave
d = (r/1+rt) solving for r

I just can't seem to solve for r on this one. I know this question is pretty simple, but I'm studying on my own so I can't ask my instructor.
Hi kingsolomonsgrave,

I'm not sure why you enclosed the right side of your equation in parentheses. And your right side is a bit ambiguous. Is it

$d=\frac{r}{1+rt}$

I'll assume it is and proceed from there.

First, multiply both sides of your equation by 1 + rt

$d+drt = r$

Next, transpose drt to the right side.

$d = r - drt$

Factor an r out of the right side.

$d = r(1-dt)$

Finally, divide both sides by 1 - dt

$\frac{d}{1-dt} = r$

thanks!!!