1. Goal: Solve a system of linear equations in two variables by the linear combination method

2. Warm Up Exercises Solve the system by substitution: y = -2xx + y = 4 -3x – y = 1-2x+ 3y = 7

3. Using the Linear Combination Method Step 1: Multiply, if necessary, one or both equations by a constant so that the coefficients of one of the variables differ only in sign. Step 2: Add the revised equations from step 1. Combining like terms will eliminate one variable. Solve for the remaining variable. Step 3: Substitute the value obtained in Step 2 into either of the original equations and solve for the other variable. Step 4: Check the solution in each of the original equations.

4. Solve the linear system using the linear combination method: 3x + y = 1x + 2y = 2 -3x + y = 7x – 2y = 6

5. Solve the linear system using the linear combination method: 2x – 3y = 68x + 2y = 4 4x – 5y = 8-2x + 3y = 13

6. Solve the linear system using the linear combination method: 7x – 12y = -223x – 2y = 2 -5x + 8y = 144x – 3y = 1

7. Solve the linear system using the linear combination method: 2x – y = 4-4x + 8y = - 12 4x – 2y = 82x – 4y = 7

8. Solve the linear system using the linear combination method: 3x + 2y = -32x – 3y = 4 -6x – 5y = 126x – 9y = -3

9. p. 142-143 8-24 even, 28, 30, 32