How do you solve for c in ab + c = 5?

Hint: To solve the above question we will use the concept of algebraic equation. We can see from the question that we have to find the value of ‘c’ so we will treat ‘c’ as a variable and ‘ab’ as a constant. Then, we will subtract ‘ab’ from both the side of the above equation and simplify it to get the required value of c.

Complete step-by-step solution:
We will use the concept of algebraic equations to solve the above question. We can see from the question that there are three unknown terms a, b, and c and we have to find the value of c so here we will treat c as a variable and a, b as a constant.
Since, we know from the question that ab + c = 5 and since we are taking a and b as a constant so we can say that ab is also a constant.
So, to find the value of c we will subtract ‘ab’ from both sides of the above equation.
$\begin{align}
  & \Rightarrow ab+c=5 \\
 & \Rightarrow ab+c-ab=5-ab \\
 & \Rightarrow c=5-ab \\
\end{align}$
Hence, the value of c is $( 5 - ab)$.
This is our required solution.

Note: When we are given an algebraic equation which has more than two different variable and we have to find the value of one of the variable and no any other equation or information is known expect a given equation then we always treat one of the unknown as variable and rest other as constants.