Texas Instruments TI-83 Plus Manual Book page 156

Chapter 5: Linear Systems
Activities
(continued)
:
Scoring Students get two
attempts to pick or input the
correct solution to the system
of equations. They earn 2
points for a correct choice or
input on the first try, and 1
point for a correct choice or
input on the second try.
There are 4 problems for a
maximum score of 8 points.
Extra Practice: Using Substitution or Elimination
1. Cathy's pay rate can be determined by the following.
Let S = hourly pay rate
Let T = overtime pay rate
Week 1: 10S + 4.5T = 93.75
Week 2: 10S + 2T = 75
To use substitution, the student could solve the Week 2 equation for 10S, 10S = 75N2T. Then,
the Week 1 equation becomes the following.
(75 N 2T) + 4.5T = 93.75
Once T is known, substitute T into either equation and solve for S.
10S + 4.5(7.5) = 93.75
Interpret the answer:
S = $6.00 per hour
T = $7.50 per hour
Cathy earns $6.00 per hour for the first 10 hours and $7.50 per hour for any overtime.
Topics in Algebra 1
Balloon Ride
Tell students to:
1. Read the introduction screen and then highlight a level (silver =
less difficult; gold = more difficult), and press Í to select it.
Students answer multiple-choice problems in the silver level and
they input their solution in the gold level.
Silver Level: Press } or † to cycle through the solutions to
choose from, and then press Í to select the solution.
Students must press a key to continue play.
Gold Level: Use } or † to select an answer or to get to the
input box. Select or input your answer and press Í. (Press
¹ to enter negative numbers.) Students must press a key to
continue play.
3. As they play the activity, students should write their work using
either elimination or substitution.
4. Record the level they played.
5. Record their scores.
10S = 75N2T
2.5T = 18.75 T = 7.5
10S = 60 S = 6
© 2001, 2002 Texas Instruments
Section 2: Using Algebra
Teacher Notes 5-33