Question

if R=ST/S-T, then s=

Answer 1

Try to get S on its own on one side of the equation. Your best start would be to get rid of that fraction. How would you go about that?

Answer 2

S is conventionally different than s

Answer 3

\[r=\frac{st}{s-t}\text{ ;multiply thru by }(s-t)\]
\[r(s-t)=st\text{ ;expand the left side}\]
\[rs-rt=st\text{ ;+rt and -st}\]
\[rs-st=rt\text{ ;factor the left side}\]
\[s(r-t)=rt\text{ ;now divide out the }(r-t)\]
\[s=\frac{rt}{r-t}\text{ ; tada!!}\]