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Solving Systems of Equations by
Thursday, October 4th, 2012
Steps to solve with substitution:
1. Isolate one of the variables in one of the
equations. (Hint: If you have a variable with a coefficient of “1”, isolate it.)
2. Substitute for that variable in the other
equation; solve for the other variable.
3. Substitute that variable in either of the
equations and now solve for the 1st variable.
(P. 154 in your textbook)
Leave as an
improper
fraction!!!
Using Substitution to Solve a Problem
• A music store offers piano
lessons at a discount for
customers buying new
pianos. The cost for
lessons and a one-time
fee for materials (inc.
music books, CDs,
software, etc.) are shown
in the advertisement.
What is the cost of each
lesson and the one-time
fee for materials?
6 lessons: $300
12 lessons: $480
(*Please include one-time fee)
Using Substitution to Solve a Problem
• An online music company offers 15 downloads
for $19.75 and 40 downloads for $43.50. Each
price includes the same one-time registration
fee. What is the cost of each download and
the registration fee?
Homework:
• P. 156 (#5-13 odd)