1. Lesson 3-4: Graphs of Linear Equations Objective: Students will: recognize linear equations graph linear equations graph horizontal and vertical lines

2. Linear Equations No product of variables No variables in denominator 1 st degree only Example 1: Which are linear? 1)3x 2 + 2y = 7 2)5x = 1 3)3xy = 1 4)y = 3x + 1 5)y = 1/x

3. Graphing Linear Equations Method 1: Standard Form Ax + By = C ► Find x – intercept: cover up y-term and solve for x ► Find y – intercept: cover up x-term and solve for y ► Slope is COVER-UP METHOD Click to link: graphing lines using interceptsgraphing lines using intercepts

4. Metod 2: Slope intercept form y = mx + b ► start at “b” on the y-axis ► use slope, “m”: move up or down then over (right) Click to link: Using slope and y-interceptUsing slope and y-intercept

5. You Try: Example 2: Graph y = 3x – 2 Example 3: Graph 3x – 4y = 12

6. Horizontal & Vertical Lines Vertical lines “hit” x-axis → x = # Horizontal lines “hit” y-axis → y = # We are saying what x or y is while the other takes on all real numbers. Example 4: Graph x = 4 No y so… can’t cross y (parallel to y-axis) Possible Solutions: (4, -2) (4,0) (4,3) Slope =No slope or undefined (Rise ÷ 0 (no run) is error) Makes N Notice x stays 4!!!!

7. Example 5: Graph y = -2 No x so can’t cross x (parallel to x-axis) Possible Solutions: (-3, -2) (0,-2) (2,-2) Slope = 0 (No Rise)÷run Makes Z (zero) Notice y stays -2!!!!