The document discusses graphing linear equations on the same coordinate plane and identifying parallel lines based on their slopes. It provides examples of graphing equations such as Y = 1/2x + 3, Y = 0.5x - 2, and Y = 1/2x and identifying that they are parallel since they have the same slope of 1/2. It also discusses graphing equations like 3y = -9x - 5 and 12x + 4y = 1, and that to graph lines on a calculator the equations need to be solved for y. The document provides an example of a parallel equation to y = 2x - 6 and asks the reader to graph cost functions for children and adults violin lessons on the

1. Day 3 of 4.5
Using a graphing calculator, graph each of
the equations on the same plane
Y = 1/2x + 3 What do they
Y = 0.5x -2 have in common?
Y = 1/2x Why????

2. Coordinate Plane (5)
•

3. • Start over and graph each of these:
3y = - 9x - 5
12x + 4y = 1
(What do you need to do before graphing
these on the calculator?)

4. • Two different lines in the same plane are
PARALLEL if they do not intersect.
• Any two non-vertical lines are parallel if
and only if they have the same slope!!
• So even without graphing the
equation, you should be able to identify
the lines that are parallel to each other on
a plane.

5. • Give an equation that would be parallel to
y = 2x - 6
• Y= -x -5
• Y = 2/3 x

6. • A violin teacher charges a one-time sheet-music
fee of $20 for adults and no fee for children. The
charge per hour is $20 for both children and
adults . The cost C for children for n lessons is
given by C = 20n and for adults by C = 20n + 20.
• Graph both on the same plane, and then
interpret the graphs. What is the difference in
costs?

8. • Cont’ P. 248 (#30-35, 40-43)