Presentation on theme: "Graphing Linear Inequalities in Two Variables graph a linear inequality in two variables model a real life situation with a linear inequality."— Presentation transcript:
Graphing Linear Inequalities in Two Variables graph a linear inequality in two variables model a real life situation with a linear inequality.
Recall… Graph n < 3 on a number line. - 3 - 2 - 1 0 1 2 3 4
Graphing an Inequality in Two Variables Graph x < 2 Step 1: Start by graphing the line x = 2 Now what points would give you less than 2? Since it has to be x < 2 we shade everything to the left of the line.
Graphing a Linear Inequality Sketch a graph of y 3
Some Helpful Hints If the sign is > or < the line is dashed If the sign is or the line will be solid When dealing with just x and y. If the sign > or the shading either goes up or to the right If the sign is < or the shading either goes down or to the left
Using What We Know Sketch a graph of x + y < 3 Step 1: Put into slope intercept form y <-x + 3 Step 2: Graph the line y = -x + 3
When dealing with slanted lines If it is > or then you shade above If it is < or then you shade below the line
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 ><
Graph on the coordinate plane. 3x - 4y > 12 - 3x - 4y > - 3x + 12 - 4 y < x - 3 m = b = - 3 Boundary Line x y
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!
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 + 0.10 d < 5.00 or 5 n + 10 d < 500