1. Warm-Up 1. Use the graph to solve the linear system. SHOW THE WORK for checking your solution. 3x – y = 5 -x + 3y = 1 (2,1)

2. Agenda for Thursday 11/29/12 Questions on solving by graphing Target Practice: PASS BACK Lesson on Solving Linear Systems by Substitution Assignment… Target 7a: I can solve linear systems by graphing, substitution, and elimination.

3. Daily Quiz Tell whether the ordered pair is a solution of the linear system. 1. (-3,1)2. (5,2) x + y = -2 2x – 3y = 4 x + 5y = 2 2x + 8y = 11 Yes! No!

5. Solving Linear Systems by Substitution y = 3x + 2 x + 2y = 11 x + 2(3x + 2) = 11 x + 6x + 4 = 11 7x + 4 = 11 -4 -4 7x = 7 7 7 x = 1 Plug 3x + 2 in for y. Solve for x. Plug 1 in for x. Solve for y. y = 3(1) + 2 y = 5 The solution is (1,5).

6. Lets try another one together! x = 2y – 5 2x – y = 11 2(2y – 5) – y = 11 4y – 10 – y = 11 3y – 10 = 11 +10 +10 3y = 21 3 3 y = 7 Plug 2y – 5 in for x. Solve for y. x = 2(7) – 5 x = 9 The solution is (9,7) Plug 7 in for y. Solve for x.

7. Try these… y – 3x = 5 x = y – 5 y = 3x – 12 2y – 3x = 36 y – 3(y – 5) = 5 y – 3y + 15 = 5 -2y + 15 = 5 -15 -15 -2y = -10 -2 -2 y = 5 x = 5 – 5 x = 0 The solution is (0,5) 2(3x – 12) – 3x = 36 6x – 24 – 3x = 36 3x – 24 = 36 +24 +24 3x = 60 3 3 x = 20 y = 3(20) – 12 y = 48 The solution is (20,48)

8. A Word Problem Laura has $4.50 in dimes and quarters. She has 3 more dimes than quarters. How many of each type of coin does she have? Step 1: Write a system of equations..10d +.25q = 4.50 d = q + 3 Step 2: Plug q + 3 in for d..10(q + 3) +.25q = 4.50.1q +.3 +.25q = 4.50.35q +.3 = 4.50 -.3 -.3.35q = 4.2.35.35 q = 12 Step 3: Plug 12 in for q. d = 12 + 3 d = 15 12 quarters 15 dimes

9. Agenda for Wednesday 11/28/12 Assignment… –Lesson 7.2a Worksheet Target 7a: I can solve linear systems by graphing, substitution, and elimination.