Making a letter the subject of a formula means, solving for the letter in terms of other letters.
Example 1: Make a the subject of the formula a+b=c.
Solution
A+b=c
a=b-c
Example 2: Given that ab+c=z, make b the subject of the formula.
Solution
Ab+c=z
Ab=z-c
ab/a=(z-c)/a Then,
b=(z-c)/a.
