1. Section 7 – 1 Solving Systems of Equations by Graphing
Objectives:
To solve systems by graphing
To analyze special types of systems

2. System of Linear Equations:
Two or more linear equations
Example: y = 2x – 3 2x + 3y = 12
y = x – 1 y = 6x + 2
There are Three Ways to Solve a System of Linear Equations:
Graphing
Substitution
Elimination

3. Solution of the System of Linear Equations:
A point (ordered pair) that both lines have in common when they are graphed. This ordered pair will make ALL the equations true when it is plugged in.
Is (-1, 5) a solution to the system?
x + y = 4
x = -1
Is (3, -2) a solution to the system?
6x – 6y = 2
3x + 9y = -7

4. Example 1 Solving a System by Graphing
Solve by graphing.
y = 2x – 3
y = x – 1
CHECK YOUR ANSWER:

5. B) Solve by graphing. y = x + 5 y = -4x CHECK YOUR ANSWER:

6. C) Solve by graphing. 𝑦=− 1 2 𝑥+2 𝑦=−3𝑥−3 CHECK YOUR ANSWER:

7. D) Solve by graphing. 2y – 4x = 2 2y – 6x = -2 CHECK YOUR ANSWER:

8. Homework: Textbook Page 343; # 2 – 12 Even (Make sure to Check ALL answers!)

9. To solve systems by graphing To analyze special types of systems
Section 7 – 1 Continued…
Objectives:
To solve systems by graphing
To analyze special types of systems

10. Example Word Problems
A) Suppose you plan to start taking a kick-boxing class. Nonmembers pay $4 per class and members pay a $10 fee plus an additional $2 per class. After how many classes will the cost be the same? What is that cost?

11. B) Suppose you are testing two fertilizers on bamboo plants A and B, which are growing under identical conditions. Plant A is 6 cm tall and growing at a rate of 4cm/day. Plant B is 10 cm tall and growing at a rate of 2cm/day. After how many days will the bamboo plants be the same height? What will their height be?

12. C). Suppose you have $20 in your bank account
C) Suppose you have $20 in your bank account. You start saving $5 each week. Your friend has $5 in his account and is saving $10 each week. Assume that neither you nor your friend makes any withdrawals. After how many weeks will you and your friend have the same amount of money in your accounts? How much money will each of you have?

13. Homework: Complete Word Problem Worksheet