91Ó°ÊÓ

Variables: - In any expression or equation, the variable is an unknown quantity. It may be any alphabet or any special symbol.

In $1.3c=3.3c+2.8$, c is the variable which is the unknown quantity.

Constants: - In any expression or equation constant are the values which are fixed.

Here, 2.8 is a constant.

Also, $1.3c$ and $3.3c$ are the product of a constant and variable.

While performing addition in an equation, the same kind of elements or like terms are added together.

In the given equation, terms with the variable cwill be added all together and while performing addition, constant terms which are multiplied with the variables are added.

$1.3c=3.3c+2.8$

Add $−3.3c$both sides of the equation and simplify.

$\begin{array}{l}1.3c−3.3c=3.3c+2.8−3.3c\\ 1.3c−3.3c=2.8+3.3c−3.3c\\ −2c=2.8\end{array}$

Multiply both sides by $-\frac{1}{2}$and simplify.

$\begin{array}{l}−\frac{1}{2}×\left(−2c\right)=−\frac{1}{2}×2.8\\ c=−1.4\end{array}$

Hence on solving , the obtained value of c is .