7.2 Graphing Equations Objectives: Learn to determine if an ordered pair is a solution of an equation. Graph equations using ordered pairs.

How do you determine if an ordered pair is a solution?? You plug in the (x, y) value into your x and y in the equations and see if the right side = the left

Determine if the ordered pair is a solution of the equation. y = 2x + 1 (3 , 7 ) 7 = 2(3) + 1 YES The ordered pair (3,7) is a solution.

Determine if the ordered pair is a solution of the equation. 4y - 3x = 22 (-2 , 4 ) 4(4) – 3 (-2)= 22 16 + 6 = 22 YES The ordered pair (-2,4) is a solution.

Determine if the ordered pair is a solution of the equation. y - 3x = -2 (-2 , 8 ) (8) – 3 (-2)= -2 ??? 8 + 6  -2 NO The ordered pair (-2,8) is not a solution.

Graphing Equations We are going to learn three ways to graph a linear equation. Today we are going to learn how to graph by “Making a Table”

Making a Table Solve the equation in y = format (slope intercept form) Pick your x values (-1, 0,1) Plug in the x values into x in the equation to find the corresponding y values Plot the (x, y) ordered pairs on the coordinate plane

y Graph: y = x y x x

y Find 3 solutions y = 2x + 1 x 1 3 (1,3) 1 (0,1) -1 -1 (-1,-1) X Values Y=2x + 1 Y Values (x,y) 1 3 (1,3) 2(1) +1 1 2(0) +1 (0,1) -1 2(-1) +1 (-1,-1) -1

Solve for ‘y’ Solve for ‘y’ means “get y all by itself”

y x 1 2(1) +5 7 (1,7) 2(0) +5 5 (0,5) -1 2(-1)+5 3 (-1,3) -2x + y = 5 Graph: -2x + y = 5 y = 2x + 5 x X Y=2x +5 Y (x,y) 1 2(1) +5 7 (1,7) 2(0) +5 5 (0,5) -1 2(-1)+5 3 (-1,3)

y x Y=2/3x +5 3 7 5 -3 3 3y = 2x + 15 (3,7) Graph: -2x + 3y = 15 (0,5) (2/3)(3) +5 5 (2/3) (0) +5 (0,5) -3 3 (2/3)(-3)+5 (-3,3)

y Graph: 3x - y = 2 y x 3x = y + 2 3x - 2 = y x

Assignment: Page 311 (2-26) even -Use graph paper - #’s 8-14 just make the table you do not have to graph -#’s 16-26 make the table and graph