Ch 6.8 Objective: To graph inequalities on the coordinate plane.

Graph n < 3 on a number line Review

More Review Graph n ≥3 on a number line

Steps for Graphing Linear Inequalities 1.For the purposes of creating the line, change the inequality sign to an equal sign. 2.Draw the line using any method you learned in Chapter 4 (x,y chart, intercept then slope, x,y intercepts, etc.) 3.Determine if the line is solid (≥, ≤) or dashed (>, <) and graph it. 4.Choose a point NOT on the line and plug into inequality. If TRUE then shade that side If FALSE then do NOT shade that side (shade the OTHER SIDE)

Graph y - 3x + 2 on the coordinate plane. x y Boundary Line y = -3x + 2 m = -3 b = 2 Test a point not on the line test (0,0) 0 -3(0) + 2 Not true! Example 1

Graph y - 3x + 2 on the coordinate plane. x y Instead of testing a point If in y = mx + b form... Shade up Shade down Solid line Dashed line >< Example 1 (again)

Graph y > 3 on the coordinate plane. x y Example 3

Graph x - 2 on the coordinate plane. x y Example 4

Graph on the coordinate plane. 3x - 4y > x - 4y > - 3x y < x - 3 m = b = - 3 Boundary Line x y Example 5

Problem If you have less than $5.00 in nickels and dimes, find an inequality and sketch a graph to describe how many of each coin you have. Let n = # of nickels Let d = # of dimes 0.05 n d < 5.00 or 5 n + 10 d < 500

nd n d