Advanced Algebra
3.4 NOTES: Solving Systems of Linear
Equations w/ Your Graphing Calculator
Name
Date
Hour
To solve systems of equations, we can use an application called plysmlt2. We will use this app for word problems because
the numbers tend to be a little nasty.
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Choose APPS Æ PLYSMLT2 Æ #2 SimultEqnSolver
Number of Eqns = ____ and Number of Unknowns = ___
Enter in information A, B, C, D from the standard equation Ax + By + Cz = D for each equation.
Press SOLVE (the “GRAPH” key)
First let’s practice with some numerical examples:
1.
x + 9y + z = 20
x + 10y – 2z = 18
3x + 27y + 2z = 58
2.
2x – 4y + 2z = 16
-2x + 5y + 2z = 4
x – 2y + 2z = 4
3.
x+y–z=0
2x + 2y – z = 1
3x + 4y = -2
Now let’s try the really fun stuff!! You must write the equations first and then give your solutions as answers in complete
sentences.
4.
The information below gives the percentages of the sophomores, juniors, and seniors that attended the three
different dances last year. Use this information to determine how many sophomores, juniors, and seniors are in the
school. (Write a system of three equations.)
Homecoming
Winter Dance
Spring Dance
Sophomores
40%
80%
50%
Juniors
80%
40%
70%
Seniors
80%
40%
80%
Total
488
412
491
6.
To raise money for new football uniforms, your school sells silk-screened T-shirts. Short sleeve T-shirts cost the
school $5 each and are sold for $8 each. Long sleeve T-shirts cost the school $7 each and sell for $12 each. The
school spends a total of $2500 on T-shirts and sells all of them for a total of $4200. How many of each type of
shirt are sold?
7.
Halloween is coming in about 5 weeks! So bags of trick-or-treat candy are on sale. Monica bought 2 bags of
Snickers, 4 bags of Reese’s and 1 bag of M&M’s for $13.60. Jose bought 3 bags of Snickers, 3 bags of Reese’s and 1
bag of M&M’s for $13.90. Liz spent $11.55 on 1 bag of Snickers, 2 bags of Reese’s and 3 bags of M&M’s. How
much does each type of candy cost?