Page 664 - Algebra 1

b. x<4 SOLUTION
Graph the boundary line x = 4 using a dashed line because the inequality contains the symbol <.
Test (0, 0).
x<4
0 < 4 Evaluate for (0, 0).
The point (0, 0) satisfies the inequality, so it is a solution. The half-plane that contains the point should be shaded.
To graph an inequality using a graphing calculator, the inequality must first be solved for y.
Graphing Linear Inequalities with Technology
Graph each inequality using a graphing calculator.
-8
-4
8
-4
-8
Example
3
a. 16x+4y≤8 SOLUTION
Solve for y.
Graphing Calculator Tip
For help with graphing inequalities, see graphing calculator Lab 9 on p. 645.
16x + 4y ≤ 8
4y ≤ -16x + 8
Subtract 16x from both sides.
Divide all three terms by 4.
Simplify.
4y ≤ -16x + 8 ___
444 y ≤ -4x + 2
8
y
4
x
O
Enter the inequality into your graphing calculator to view the graph.
b. 3x-y<-4 SOLUTION
Solve for y.
3x - y < -4
-y < -3x - 4
-y > -3x - 4 ___
-1 -1 -1 y > 3x + 4
Subtract 3x from both sides. Divide all three terms by -1.
Simplify.
Caution
Remember to reverse the inequality when multiplying or dividing both sides by a negative number.
Enter the inequality into your graphing calculator to view the graph.
Lesson 97 649