Class 8 Chapter 8: Linear Equations

Class 8 Chapter 8: Linear Equations

Important Concepts and Formulas

1.      An equation is a statement of equality between two expressions involving variables and constants.

2.      An equation has two sides separated by the symbol (=). The two sides are LHS and RHS.

3.      Linear expressions are those in which the highest power of the variable is 1.

4.      Linear equation in one variable is of the form ax + b = c, where a, b and c are constants and a ≠ 0.

5.      The value of the variable, which makes both sides of the equation same is called the solution of the equation. For example, x = 3 is the solution of equation 4x – 5 = 7.

6.      If LHS and RHS are interchanged, the equation remains the same.

7.      Methods of solving linear equations in one variable:
·        Add the same term (constant and/or variable) to both sides of an equation.
·        Subtract the same term (constant and/or variable) from both sides.
·        Multiply both sides by the same term (constant and/or variable).
·        Divide both sides by the same term (constant and/or variable).

8.      You can use the general strategy to solve word problems as follows:
·        Read the question carefully and identify the unknown quantity.
·        Use a letter x to represent the unknown quantity.
·        Express other quantities in terms of x.
·        Form an equation based on the given information.
·        Solve the equation.
·        Write down the answer statement.