2. Graphs, Linear Equations, and Functions
Chapter 4
Graphs, Linear Equations, and Functions

3. Linear Equations in Two Variables
4.3
Linear Equations in Two Variables

4. 4.3 Linear Equations in Two Variables
Objectives
Write an equation of a line, given its slope and y-intercept.
Graph a line, using its slope and y-intercept.
Write an equation of a line, given its slope and a point on the line.
Write an equation of a line, given two points on the line.
Write an equation of a line parallel or perpendicular to a given line.
Write an equation of a line that models real data.
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5. 4.3 Linear Equations in Two Variables
Write an equation of a line given its slope and y-intercept.
Given the slope m of a line and the y-intercept b of the line, we can determine its equation.
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6. 4.3 Linear Equations in Two Variables
Write an equation of a line given its slope and y-intercept.
If we know the slope of a line and its y-intercept, we can write its equation by substituting these values into the above equation.
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7. 4.3 Linear Equations in Two Variables
Writing an Equation of a Line
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8. 4.3 Linear Equations in Two Variables
Graph Lines Using Slope and y-Intercept
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9. 4.3 Linear Equations in Two Variables
Write an equation of a line, given its slope and a point on the line.
If we know the slope m of a line and the coordinates of a point on the line, we can determine its equation.
Copyright © 2010 Pearson Education, Inc. All rights reserved.

10. 4.3 Linear Equations in Two Variables
Write an equation of a line, given its slope and a point on the line.
If we know the slope of a line and the coordinates of a single point on the line, we can write the equation of the line by substituting these values into the equation above.
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11. 4.3 Linear Equations in Two Variables
Finding the Equation of a Line, Given the Slope and a Point
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12. 4.3 Linear Equations in Two Variables
Finding an Equation of a Line, Given Two Points
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13. 4.3 Linear Equations in Two Variables
Finding an Equation of a Line, Given Two Points
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14. 4.3 Linear Equations in Two Variables
Equations of Horizontal and Vertical Lines
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15. 4.3 Linear Equations in Two Variables
Finding Equations of Parallel or Perpendicular Lines
Recall that parallel lines have the same slope and perpendicular lines have slopes with product –1.
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16. 4.3 Linear Equations in Two Variables
Finding Equations of Parallel or Perpendicular Lines
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17. 4.3 Linear Equations in Two Variables
Finding Equations of Parallel or Perpendicular Lines
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18. 4.3 Linear Equations in Two Variables
Finding Equations of Parallel or Perpendicular Lines 6 –6 6 –6
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19. 4.3 Linear Equations in Two Variables
Finding Equations of Parallel or Perpendicular Lines
Recall that parallel lines have the same slope and perpendicular lines have slopes with product –1.
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20. 4.3 Linear Equations in Two Variables
Finding Equations of Parallel or Perpendicular Lines
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21. 4.3 Linear Equations in Two Variables
Finding Equations of Parallel or Perpendicular Lines
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22. 4.3 Linear Equations in Two Variables
Finding Equations of Parallel or Perpendicular Lines 6 –6 6 –6
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23. 4.3 Linear Equations in Two Variables
Forms of Linear Equations
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24. 4.3 Linear Equations in Two Variables
Determining a Linear Equation to Describe Real Data
A veterinarian charges $45 to visit a farm where cattle are raised. The price to vaccinate each animal is $18. Write an equation that defines the total bill that the veterinarian will submit to vaccinate all the cattle at the farm.
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