Lesson 4.2 Graph Linear Equations

1
Lesson 4.2 Graph Linear Equations

• OBJ To graph linear equations in a coordinate
  plane.

2
Equations in two variables

• 2x 5y 8 y 2x 8
• The solution of an equation in two variables, x
  and y, is an ordered pair (x, y) that produces a
  true statement when the values of x and y are
  substituted into the equation.

3
Examples

• Is (3,4) a solution of 3x y 7?
• Is (1, -4) a solution of 3x y 7?
• Is (4, -1/2) a solution to x 2y 5?

4
Graphing

• Graph of an equation in two variables is the set
  of points in a coordinate plane that represent
  all solutions of the equation.
• We graph by making a table
• Graph 2x y 2
• Graph 2y 6x 10

5
Standard Form

• Standard form of a linear equation is AxByC
  where A, B, and C are real numbers and A and B
  are not both zero.

6
Horizontal and Vertical Lines

• The graph of yb is a horizontal line. The line
  passes through the point (0, b).
• The graph of xa is a vertical line. The line
  passes through the point (a, 0)

7
Linear Function

• The equation AxByC represents a linear function
  provided B does not equal 0.
• Graph y ½ x 1 with a domain x is less than or
  equal to 0. Then identify the range.