9.2: Solving Simultaneous Linear Equations by Elimination Method

1) Lesson Objectives:

You should be able to 

• solve simultaneous equations by Elimination Method

• to check you answer using a calculator

Please watch the video lessons after this section.

Solve the following simultaneous equations:

x + 3y  =  5

2x - 5y = -12

Steps:

1. Label both equations as (1) and (2)

2. Choose a variable that you would like to eliminate

3. Make sure the coefficient of the variable that you have chosen to eliminate is the same for both the equations

4. If it is not the same, multiply a constant to find the LCM for both

5. Add or subtract the equations to eliminate the variable chosen

If the variable have the same signs - Subtract the 2 equations

If the variable have different signs - Add the 2 equations

6. Once you find one variable, remember to substitute and find the other variable

7. You must have 2 values, one for each variable as your answer 

8. Check if you answer is correct by using your calculator