1. MFM 2P Minds On Add or Subtract the following equations in order to make “y” equal 0.

2. MFM 2P Learning Goal: I can determine the point of intersection between two lines algebraically using elimination. Lesson 9 – Finding the POI by Elimination

3. MFM 2P If we can ELIMINATE on of the variables, we can solve for the other variable. Then the steps are the same as they were for substitution: Sub the value of the variable you found back into EITHER equation and solve for the other variable Check your answer using a Left Side/Right Side check with the equation you did not choose in the previous step State what the POI is: ( The POI is (x, y) ) Lesson 9 – Finding the POI by Elimination

4. MFM 2P Example: Solve the following linear system Lesson 9 – Finding the POI by Elimination

5. MFM 2P Example: Solve the following linear system Lesson 9 – Finding the POI by Elimination

6. MFM 2P Example: Solve the following linear system Lesson 9 – Finding the POI by Elimination

7. MFM 2P Lesson 9 – Finding the POI by Elimination How do you decide whether to add or subtract? What needs to be true about the coefficients (numbers) in the equations before you can add or subtract?

8. MFM 2P Example: Solve the following linear system Lesson 9 – Finding the POI by Elimination

9. MFM 2P 5x – 3y = 188 6x – 11y = 344 Lesson 9 – Finding the POI by Elimination

10. MFM 2P 9x – 4y = 235 15x + 2y = 409 Lesson 9 – Finding the POI by Elimination

11. MFM 2P Practice  Handout Lesson 9 – Finding the POI by Elimination