Warm up

1

• Warm up
• Solve the given system by substitution
• 2x y 7
• 3x 3y - 3
• Solve the given system by elimination
• 2) -3x 4y -4
• 3x 6y 6

2
Summary of Methods

1. Substitution Requires that one of the variables
   be isolated on one side of the equation. It is
   especially convenient when one of the variables
   has a coefficient of 1 or -1.
2. Elimination Can be applied to any system, but it
   is especially convenient when a variable appears
   in different equations with coefficients that are
   opposites.
3. Graphing Can provide a useful method for
   estimating a solution.

3
Summary of Solving Systems by Westerville South
H.S.

• All I do is Solve
• http//www.schooltube.com/channel/westervillesouth
  math/

4
Best MethodGraphing, Substitution, Elimination?
1. y 4x 3 5x 2y 6
2. 4x 5y 13 2x 5y 5
5
Best Method
5. 3x 2y 6 y 2x 4 6. x y 4 2x
3y 7
6
Solving Word Problems Using Systems
7
Steps

1. Define all variables.
2. Write the system of equations.
3. Solve using best method showing all steps.
4. State your solution in sentence form.
5. Check your solution.

8
1. You are selling tickets for a high school
basketball game. Student tickets cost 3 and
general admission tickets cost 5. You sell 350
tickets and collect 1450. How many of each type
of ticket did you sell?
Define variables
Solve
S of Student Tickets
G of General Admin Tickets
G 200
System of equations
S G 350
S 150
3S 5G 1450
State your solution(s)
I sold 200 general admission tickets and 150
student tickets.
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Solve
Define variables
S of Student Tickets
G of General Admin Tickets
System of equations
S G 350
 
3S 5G 1450
G 200
State your solution(s)
S 150
I sold 200 general admission tickets and 150
student tickets.
10
2. Last Saturday Missy bought pants and shirts.
Each shirt cost 125 and each pair of pants cost
225. She came home with 26 items and spent
exactly 4950. How many pants and shirts did
Missy buy?
11
Solve
Define variables
S of Shirts
P of Pants
System of equations
S P 26
 
125S 225G 4950
P 17
State your solution(s)
S 9
Missy bought 17 pairs of pants and 9 shirts.
12
3. You are in charge of decorating the gym for
the Homecoming dance. You purchased 6 bags of
balloons and 5 bags of large sparkling hanging
stars all for 19.20. You soon realized that
this was not enough to decorate the entire gym.
On your second trip to the store, you bought 8
bags of balloons and 2 bags of large sparkling
hanging stars all for 15.80. What was the price
for each item?
13
Solve
Define variables
B price of a bag of balloons
S price of a bag of stars
System of equations
6B 5S 19.20
 
8B 2S 15.80
B 1.45
State your solution(s)
S 2.10
The price of the bag of balloons is 1.45 and the
bag of stars is 2.10.
14
4. Wally World had a sale on DVDs and CDs for
Labor Day weekend. Katie bought 3 DVDs and 2 CDs
and spent 42. Emily bought 5 DVDs and 1 CD and
spent 56. How much does each DVD and CD cost?
15
Solve
Define variables
D cost of DVD
C cost of CD
System of equations
3D 2C 42
 
5D C 56
D 10
State your solution(s)
C 6
A DVD cost 10 and a CD costs 6.