An equation is an equality connecting some unknowns. The unknowns are represented by "letters" and are called "the variables". If the equation has only one unknown, it is called "an equal in one variable". The word "Linear" means "of degree one".
Hence if only a single variable with degree one occurs in an equation, it is called a linear equation in one variable.
Linear Equations in One Variable
An equation of one variable and of first order (i.e., its highest power is one) is called a linear equation. Such an equation has only one solution. A solution is also called the 'root' of the given equation.
Summary
A solution of a linear equation is the value of the variable which makes LHS = RHS. It is also called the "root" of the equation.
To solve a linear equation, we transpose all the terms containing the variable to one side and the constant terms to the other. The equation then reduces to the form ax = b.
