Graphing Linear Equations: Slopes

Do Now: Using your calculator to help, graph the line y = 2x - 4

1. Copy the table from the calculator

Do Now: Using your calculator to help, graph the line y = 2x - 4

2. Plot the (x,y) points. Remember start at the origin (the point where the x and y axes intersect – coordinates are (0,0) ) Go right (positive) or left (negative) first (x) and then up (positive) or down (negative) next (y).

3. Connect the points using a straight edge.

***How do we know the graph should be a straight line?

Graph y = - 3x + 2 Graph y = ½ x - 4

What do the numbers in the equations represent?

y = mx + bWhere

m = the slope of the line

b = the y-intercept

How can we determine the slope of a line?

Find the slope of the line in the graph:

1. Pick two points on the line

2. Use the slope formula

Practice – Find each of the following slopes

Practice finding slope with no graph:

Find the slope of the line passing through (2,1) and (-3,-1)

Find the slope of the line passing through (-2,3) and (-4, 0)

Special Lines: Find the slope of each of the following

Conclusion: Conclusion:

Special Lines:

Horizontal Lines:

Slope is

Equation is

Vertical Lines:

Slope is:

Equation is:

Graph each of the following pairs of lines. What do you observe?

1. a. y = 2x + 3 What do these lines have in common?

b. y = 2x – 1

2. a. y = - 3x – 2 What do these lines have in common?

b. y = - 3x + 3

3. a. y = ½ x – 3 What do these lines have in common?

b. y = ½ x + 5

CONCLUSION: