formula for specified variable

Question

solve the following formula for the specified variable. A = 1⁄4 f(r + z) for r

Answer 1

Since we are trying to find r, we need to get r on one side of the equation by itself:

Step 1 A=1/4 f(r + z) Original Equation

Step 2 4A= f(r + z) Multiply both sides of the equation by 4 to get rid of the 1/4

Step 3. 4A/f= r + z Divide both sides of the equation by f to get rid of f on the right side

Step 4. (4A/f) - z= r Subtract z from both sides of the equation to get r by itself on the right

Please Note: On step 2, you could distribute f to r+z instead; however, you get the same answer either way.

Alternative Step 3. 4A= fr + fz Distribute f to both r and z

Alternative Step 4. 4A - fz= fr Subtract fz from both sides of the equation

Alternative Step 5. (4A - fz)/f = r Divide both sides of the equation by f to get r by itself.

(4A - fz)/f = (4A/f) - z

Answer 2

A = 1⁄4 f(r + z)

4A = fr + fz

4A - fz = fr

(4A - fz) / f = r