A statement of equality of two algebraic expressions, which involve one or more unknown quantities is known as an equation. If there are two unknown quantities then equation is called linear equation in two variables.
A linear equation is an equation which involves linear polynomials.A value of the variable which makes the two sides of the equation equal is called the solution of the equation.
Same quantity can be added/subtracted to/from both the sides of an equation without changing the equality. Both the sides of an equation can be multiplied/divided by the same non-zero number without changing the equality.
Note :- To find value of variables in any equation we required number of equation equal to number of variables in equation.
General form of pair of linear equation
where a1, b1, c1 & a2, b2, c2 are constants.