Simultaneous--Equations-Graphically.pptx

Simultaneous-Equations-Graphically
grade8
help solving SE by graphing

1. Starter: We learned in the previous lesson how to graph linear equations . Lets warmup by graphing the following equation : X+Y = 2

2. We are going to learn how to solve simultaneous equations graphically.

3. 9x – 8y = -36 x + 2y = 6 (1) (2) Taking eq (1) x + 2y = 6 x y 3 6 Taking eq (2) 9x – 8y = -36 x y 4.5 -4 Eg 1 x + 2y = 6 9x – 8y = -36 x = -1, y = 3.5

4. Now it’s your turn Find your self a partner and solve the following system : X+Y =6 Y=X-2

5. If the graphs of a system of equations are as shown below. What do you think is the solution of this system?

6. Simultaneous equations Solving by substitution

7. Example #1 Solve the simultaneous equations by substitution Substitute Into Subtract 2x from both sides Add 1 to both sides Substitute back into one of the original equations

8. Example #2 Solve the simultaneous equations by substitution Get one unknown by itself on one side Use method of substitution just like you did in the previous examples

9. Now it’s your turn solve the following system of equations by substitution X+2Y=4 2X+Y=2