1. The slope-intercept form of a line: y = mx + b

2. Graph the following family of lines using the graphing calculator:
y = 3x + 2
y = 5x + 2
y = -4 x + 2
y = 1/2 x + 2
All of these equations are written in
y = mx+b form. What does m represent in each equation?
Check your hypothesis by using the table feature of the calculator.

3. Graph the following family of lines using the graphing calculator:
y = 3x + 2
y = 3x - 4
y = 3x
y = 3 x + 8
All of these equations are written in
y = mx+b form. What does b represent in each equation?
Check your hypothesis by using the table feature of the calculator.

4. Given y = mx + b m represents the slope of the line
b represents the y-intercept -- the point where the line intercepts or crosses the y-axis.

5. Graphing lines in the form y = mx + b is very easy since you know one point, the y-intercept, and the slope.
Graph each of the following:
y = 2x + 5
y = - x – 3
y = 4x
y = - 2

6. Finding the equations of lines is very easy if you know the y-intercept and slope.
Find the equation of the line:
that passes through the origin with slope – 2.
with y–intercept of 4 and slope 2/3.
that is horizontal and passes through the point ( 2, 5)

7. What if the equation is not given in y = mx + b form?
Graph the equation whose standard form is 3x + 2y = 6.
Strategy 1: Rewrite the equation in y = mx + b form.
Strategy 2: Find the x-intercept and the y-intercept.

8. To find the x-intercept and the y-intercept of a line written in standard form:
Let x = 0 to find the y-intercept.
Let y = 0 to find the x-intercept.
Example: Find the x-intercept and the y-intercept of the line 3x – 5y = 15. Then graph the line.

9. Graphing equations in different forms:
Point-slope form: y – y1 = m(x – x1)
Use a point (x1, y1 ) and the slope, m.
Standard form Ax + By = C
Rewrite in y = mx + b form OR
Find the x-intercept and the y-intercept OR
Make a table of solutions.
Slope-intercept form y = mx + b
Use the y-intercept and the slope.

10. Assignment: 6.4 #19-45 odds Due Wednesday 1/14/04
6.5 #13-25 all. Use graph paper. Write the equation next to each graph.
Due Thursday 1/15/05