Do Now In words, describe how to plot (5, –2) in words onto a coordinate plane. Graph y = –x – 2 with the domain of -2, -1, 0, 1, and 2

Worksheet Key 4.2 - Graphing Linear Equations 12/6/2018 5:38 AM

Graphing Linear Equations Section 4.2 4.2 - Graphing Linear Equations 12/6/2018 5:38 AM

Linear Equation in Two Variables Standard Form: Ax + By = C A, B, C are whole numbers and A and B both cannot be zero. For it to be linear, the x has to be raised to the 1st power (exponent)

Is it linear? x – 1.5y = –1.6 y = –2x x + y2 = 9 x = 5 YES NO

Identifying from a table Take the difference from the top to the bottom from the x and y’s Do it for all of the points If it is consistent, it is LINEAR. If it not consistent, then it NOT LINEAR.

Example 1 Is this table linear? x y –2 –7 –1 –5 –3 1 2

Example 2 Is this table linear? x y 3 2 1 4 6 –1 8 –2

Your Turn Is this table linear? x y –3 –11 1 5 13 9 24 37

Graphing using a Table Plug in at least three x’s to obtain the y’s One positive x-coordinate Zero-coordinate One negative x-coordinate Connect the lines Check

Example 1 Graph the linear equation, 2x + y = 5 Plug in –1 for x

Example 1 Graph the linear equation, 2x + y = 5 Plug in 0 for x

Example 1 Graph the linear equation, 2x + y = 5 Plug in 1 for x

Example 1 Graph the linear equation, 2x + y = 5 x y –1 7 5 1 3

Example 2 Graph the linear equation, –2x + 4y = 8 x y –2 2 –2 1 2 3

Your Turn Graph the linear equation, –2x + y = –3 x y –2 2 –2 –7 –3 2 1

Example 3 Graph the linear equation, y = 3x x y –1 2 –1 –3 2 6

Your Turn Graph the linear equation, y = –1/3x + 2 x y –3 6 –3 3 2 6

Example 4 Graph the linear equation, y = 2 x y –2 2 –2 2

Your Turn Graph the linear equation, x = 2 x y –3 3 2 –3 3

Assignment Worksheet