Year 7 Interactive Maths - Second Edition

Solution of Equations

In the following sections, we will consider solving equations involving addition, subtraction, multiplication and division.

Equations Involving Addition

Consider the equation

If we subtract 8 from both sides of the equation, then we obtain:

We notice that the statement

remains a true statement when 8 is subtracted from both sides of the equation.

This suggests that equations behave like a balance.  If the same mass is taken away from both scales of a balance, it still remains balanced.  This implies that we can subtract the same number from both sides of an equation to get a new equation.

Consider the equation x + 3 = 7.

From the preceding discussion, we can state that:

The same number can be subtracted from both sides of an equation.

Example 3

Solution:

Key Terms

solving the equation, equations behave like a balance

Study Another Topic in Chapter 7: Equations

[ Equations ] [ Solution of Equations ] [ Equations Involving Subtraction ] [ Equations Involving Multiplication ] [ Equations Involving Division ] [ Solving Word Problems ] [ Problem Solving Unit ] [ Symbols ] [ Index ]