Chapter 4.7, Problem 4OE

To determine

To solve the equation $s=a+b+c$ , for c .

Answer to Problem 4OE

  $c=s-b-a$

Explanation of Solution

Given:

The equation, $s=a+b+c$

Concept Used:

• To get rid of a number in addition from one side, subtract the same number from both sides of equal sign.
• To get rid of a number in subtraction from one side, add the same number both sides of equal sign.
• To get rid of a number in multiplication from one side, divide the same number from both sides of equal sign.
• To get rid of a number in division from one side, multiply the same number both sides of equal sign.

Calculation:

To solve the given equation $s=a+b+c$ for c , isolate the variable term c on one side by performing some basic algebraic operations to get rid of the other numbers and terms associated with it.

Here to isolate c on right side, first subtract b on both sides and then simplify further by subtracting a from both sides as shown below,

  $\begin{array}{c}s=a+b+c\\ s-b=a+b+c-b\\ s-b=a+c\\ s-b-a=a+c-a\\ s-b-a=c\\ \Rightarrow c=s-b-a\end{array}$

Thus, on solving for the indicated variable it gives $c=s-b-a$ .