228 Chapter 3 Graphing Linear Equations in Two Variables 5 4 y 1 21 1 Alternative Solution: Create a table of values for the equation The choice for the y-coordinate must be 3, but x can be any real number. x can be any number. y must be 3. (0, 3) (2, 3) 21 Graphing a Vertical Line x y 0 3 1 3 2 3 5 4 y 1 1 Graph the equation 4x 8. Solution: Because the equation does not have a y variable, we can solve the equation for x. is equivalent to 4x 8 x 2 This equation is in the form x k, indicating that the line is vertical and must cross the x-axis at x 2 (Figure 3-12). Example 8 y 3. y 3 54 3 1 2 3 4 5 2 3 4 5 x 3 2 Figure 3-11 Answers 13. 14. 5 4 3 2 1 y 54 3 1 2 3 4 5 5 4 3 2 1 y 21 54 3 1 2 3 5 21 1 2 3 4 5 x 4 1 3 4 5 x 2 Graphing a Horizontal Line Graph the equation y 3. Solution: Because this equation is in the form y k, the line is horizontal and must cross the y-axis at y 3 (Figure 3-11). Example 7 Classroom Example: p. 235, Exercise 68 Classroom Example: p. 235, Exercise 70 x 2 5 4 y 1 54 3 1 2 3 4 5 21 1 2 3 4 5 x 3 2 Figure 3-12 54 3 1 2 3 4 5 2 3 4 5 x 3 2 (1, 3) Skill Practice Graph the equation. 13. y 2 Skill Practice Graph the equation. 14. 3x 12 TIP: Notice that a horizontal line has a y-intercept, but does not have an x-intercept (unless the horizontal line is the x-axis itself ).
miller_introductory_algebra_3e_ch1_3
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