1. Bell Ringer
Don bought a tie for $15. If tax was 9%, how much did he pay for the tie? 1. Calculate Tax: $15 • 0.09 = $ Final Cost (Price + Tax): $15 + $1.35 = $16.35

2. This Week in Algebra…
Monday – Graphing Linear Equations Tuesday – More Graphing Wednesday – Introduction to Slope Thursday – Finding Slope on a Graph Friday – Review: Coordinate Points, Graphing Linear Equations, and Slope. (Next week: Quiz Tuesday – Plotting points, Graphing Linear Equations, and Finding Slope.)

3. Sit: Marcella’s Bagels
Due Friday, January 11th
Remember the problem:
1. Marcella gave half her bagels and two more to:
a. The needy
b. Some surfers
c. Her friend Susan.
2. She had two left when she got home.
3. How many bagels did she buy?

4. Homework

5. Graphing Linear Equations
GRE 401: Locate points in the coordinate plane
GRE 503: Match linear graphs with their equations

6. Linear Equations y x
Linear
Not Linear

7. Linear Equations
The equations we will be graphing will have two variables, x & y.
y = 2x + 1
A solution to the equation is any ordered pair (x, y) that makes the equation true.
The ordered pair (3, 7) is a solution since 7 = 2(3) + 1.

8. Solutions to Linear Equations
There are an infinite number of points that would satisfy this equation.
When you plot these points on a coordinate plane, you create a graph of the equation.
Every point on the line is a possible solution to the equation!
y = 2x – 1 -1 1 1 2 3 3 5 4 7

9. Graphing Linear Equations
y = 2x – 1
This is the graph of the equation y = 2x – 1. . . -1 . 1 1 . 2 3 . 3 5 4 7

10. Graphing Linear Equations
y = -3x + 2 2 . 1 -1 2 -4 .
We only need three points to graph a line. .

11. Horizontal and Vertical Lines
Horizontal Lines
Equations like y = 3, y = -6, y = 8, etc. result in horizontal lines.
Vertical Lines
Equations like x = 4, x = -4, x = 12, etc. result in vertical lines.

12. y is always 4, so x can be any number!
Horizontal Lines
y = 4 4 . . . 1 4 2 4
y is always 4, so x can be any number!

13. x is always -4, so y can be any number!
Vertical Lines
x = -4 . -4 1 . -4 3 . -4 6
x is always -4, so y can be any number!