How do I Make r the subject of this formula? t=12(s-r) divided by r

I cannot find a way to rearrange this formula; please help!

Any tips and hints are greatly appreciated
Thanks guys, Roman C :)

2 Answers
Jul 4, 2018

r=(12s)/(t+12)r=12st+12

Explanation:

"we are given "t=(12(s-r))/rwe are given t=12(sr)r

"multiply both sides by "rmultiply both sides by r

rt=cancel(r)xx(12(s-r))/cancel(r)

rt=12(s-r)larrcolor(blue)"distribute"

rt=12s-12r

"add "12r" to both sides"

rt+12r=12s

"take out "r" as a "color(blue)"common factor"

r(t+12)=12s

"divide both sides by "(t+12)

r=(12s)/(t+12)

Jul 4, 2018

r=(12s)/(t+12)

Explanation:

Making r the subject of this formula just means we want to solve for r in terms of the other variables.

Right now, we have

t=(12(s-r))/r

We don't want r in the denominator, so let's multiply both sides by it to get

rt=12(s-r)

Distributing the 12 on the right gives us

rt=12s-12r

To solve for r, we want to get all of our r terms on one side. Let's add 12r to both sides to get

rt+12r=12s

Both left side terms have an r, so we can factor that out.

r(t+12)=12s

Our last step would be to divide both sides by t+12 to get

r=(12s)/(t+12)

Hope this helps!