1. Simultaneous Linear Equations Objectives (a)Plot linear equations on a graph (b)Plot two linear equations (c)Solve a pair of linear equations (d)Solve a pair of linear equations by elimination

2. Introduction Lets have a look at a relatively straight single equation This is a linear equation because there are no terms involving or Suppose we choose a value of

3. x0123 x0123 -313

4. Suppose we take a second formula x0123 x0123 42.51-0.5

5. When we solve simultaneous equations we are looking for the intersection of the two straight lines because this is the point that satisfies both equations at the same time. When this occurs at the point

6. Solve a pair of linear equations by elimination Take the two previous linear equations............................EQ1............................EQ2 We need to make the x or y coefficients the same so that we can eliminate either x or y If we multiply EQ 1 by -2 we would get............................EQ3

7. To solve the equation we need to take EQ2 away from EQ3...........................EQ3............................EQ2 Substitute x=2 into one of the equations

8. Comparison between graphical and elimination Graphical Elimination

9. Simultaneous Linear Equations Worked examples

10. Solve the following pairs of simultaneous equations by graphical method (a) (b)

11. (a) x01234 x01234

12. (b) x01234 x01234

13. Solve the following pairs of simultaneous equations by elimination method (a) (b)