Question

B=
r+k
3
110
f for r

Answer 1

`r=(3B)/(f)-k`.

Explanation:

1. Write the expression.

`B=((r+k)/(3) )f`

2. Divide by f on both sides.

`(B)/(f) =[((r+k)/(3) )f]/f\\ \\(B)/(f) =(r+k)/(3)`

3. Multiply both sides by 3.

`(3B)/(f) =r+k`

3. Substract k from both sides.

`(3B)/(f)-k =r+k-k\\ \\(3B)/(f)-k =r`

4. Reorganize.

`r=(3B)/(f)-k`.