Warm-Up: September 24, 2012  Armando is comparing parking prices at a local concert. One option is a $7 entry fee plus $2 per hour. A second option is a $5 entry fee plus $3 per hour. After how many hours would the two options cost the same amount? How much would they each cost for that many hours?

Homework Questions?

Section 3.2

Purpose  Learn how to solve systems of equations using elimination.

Outcome  Solve systems of equations using elimination.

Essential Question  How can we solve a system of two equations?

Elimination Method 1. Arrange each equation in standard form, Ax + By = C 2. Multiply one or both equations by a number so the coefficients of one variable are opposite (one positive, one negative). 3. Add the two equations together. This will eliminate one variable. 4. Solve the resulting equation for the remaining variable. 5. Substitute this value into either equation to solve for the other variable. 6. Check your answer.

No Solutions or Infinite Solutions  If when you add the two equations, both variables are eliminated, then there is either zero or infinite solutions.  If the resulting equation is true (0 = 0), then there are infinite solutions.  If the resulting equation is false (0 = 4 or 0 = -3, etc.) then there are no solutions.

Example 1 3x + 4y = 23 -3x + y = 2

You-Try #1 -2x + 3y = -14 2x + 2y = 4

Example 2 7b – 5c = 11 -4c – 2b = -14

You-Try #2 5x + 3y = 2 2x + 20 = 4y

Assignment  Page 169 #9-25 every other odd, 43, 46  (9, 13, 17, 21, 25, 43, 46)

September 25, 2012  Pick up a worksheet and start working on it in your assigned seat.  Have your homework out for Mr. Szwast to check.

Homework Questions?

September 26, 2012  Pick up a “3.2 Practice A” worksheet.  Start working on the worksheet in your assigned seat.  Have your homework out for Mr. Szwast to check.

Homework Questions?

3.2 Worksheet  You have the rest of class to work on the 3.2 worksheet.

3.2 Practice A answers