1. TODAY IN ALGEBRA…  Warm Up: Solving a system by Elimination  Learning Goal: 7.4 You will solve systems of linear equations by Elimination with multiplication first  Independent Practice  MID CH.7 TEST-MONDAY/TUESDAY!

2. WARM UP: Solve the systems using ELIMINATION.

3. Same signs: SUBTRACT WARM UP: Solve the systems using ELIMINATION.

4. Different signs: ADD WARM UP: Solve the systems using ELIMINATION.

5. 7.3 SOLVING LINEAR SYSTEMS BY ELIMINATION STEPS FOR SOLVING A LINEAR SYSTEM BY ELIMINATION WITH ELIMINATION FIRST: STEP 1: Align the variables with x and y on the same side of each equation. Choose a variable to eliminate and multiply each equation by the coefficients. Then ADD or SUBTRACT the equations. STEP 2: SOLVE the equation for the remaining variable. STEP 3: Substitute the solution from STEP 2 into either equation to solve for given variable. THIS IS MUCH EASIER WITH AN EXAMPLE!

6. 7.4 ELIMINATION WITH MULTIPLICATION FIRST I’ll eliminate the x’s first Now I have matching coefficients! Solve this system using elimination.

7. 7.3 SOLVING LINEAR SYSTEMS BY ELIMINATION EXAMPLE 1 Continued: Same signs: SUBTRACT

8. 7.4 ELIMINATION WITH MULTIPLICATION FIRST I’ll eliminate the x’s first Now I have matching coefficients! Solve this system using elimination.

9. 7.3 SOLVING LINEAR SYSTEMS BY ELIMINATION EXAMPLE 2 Continued: Same signs: SUBTRACT

10. 7.4 ELIMINATION WITH MULTIPLICATION FIRST I’ll eliminate the y’s first Sometimes you only need to multiply one equation! Now I have matching coefficients! Solve this system using elimination.

11. 7.3 SOLVING LINEAR SYSTEMS BY ELIMINATION EXAMPLE 3 Continued: Same signs: SUBTRACT

12. 7.4 ELIMINATION WITH MULTIPLICATION FIRST I’ll eliminate the x’s first Now I have matching coefficients! Solve this system using elimination.

13. 7.3 SOLVING LINEAR SYSTEMS BY ELIMINATION EXAMPLE 4 Continued: Same signs: SUBTRACT

14. 7.4 ELIMINATION WITH MULTIPLICATION FIRST

15. I’ll eliminate the y’s first Now I have matching coefficients! Solve this system using elimination.

16. 7.3 SOLVING LINEAR SYSTEMS BY ELIMINATION EXAMPLE 4 Continued: Same signs: SUBTRACT x: soccer balls cost $14.50 each, y: bags cost $5.00 each

17. HOMEWORK #4: Pg. 454: 4-26 even, 38 If finished, work on other assignments: HW #1: Pg. 430: 3-10, 12-15, 22, 23, 32 HW #2: Pg. 439: 4-24 even, 31 HW #3: Pg. 447: 4-22 even