Solving Systems word problem by hcj

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									3.2 – SOLVING SYSTEMS WORD
PROBLEMS
Today’s Goal
  Review how to solve systems of equations using
   the Elimination Method.
  Write and solve a system of linear equations for a
   word problem scenario.
Agenda
  Elimination Notes
  Review Problems from Monday
  System Word Problems Practice
3.2 – SOLVING SYSTEMS BY
ELIMINATION
1. Multiply one or both of the equations by a
   number so that the coefficients of x or y
   are opposite in sign.
2. Add the equations together thus
   eliminating a variable. Solve for the
   variable left.
3. Solve for the other variable.
EXAMPLE 1 – MULTIPLYING 1 EQUATION




Solution = (-2, 6)
EXAMPLE #2 – MULTIPLYING BOTH
EQUATIONS




Solution= (-3, -4)
SYSTEMS WORD PROBLEMS
Strategy for Word Problems
  Define your variables, x and y.
  Write two linear equations to model the word
   problem scenario.
  Solve the system of equations by the Substitution
   or Elimination Method.
1. Find the value of two numbers if their sum
 is 12 and their difference is 4.

8 and 4
PROBLEM 2
You and your friend go to Taco Bell for lunch.
 You order 2 soft tacos and 3 burritos and
 spend $11.25. Your friend orders 4 soft tacos
 and 2 burritos for a total of $10. How much
 does a soft taco cost? How much does a
 burrito cost?

Soft taco = $1.25
Burrito = $2.50
PROBLEM 3
You need to get 115 cupcakes for your party.
 The vanilla cupcakes cost $.50 a piece and
 the chocolate cost $.75. Your parents are
 willing to spend $75 on cupcakes. How many
 cupcakes of each kind can you get?



45 vanilla cupcakes
70 chocolate cupcakes
PROBLEM 4
You went to the movies and got 2 large
 popcorns and 4 sodas and it cost $28.00.
 Your friends went the other day and got 3
 large popcorns and 5 sodas and it cost them
 $38.00. How much did each item cost?



Popcorn = $6
Soda = $4
HOMEWORK
Finish the back page of the 3.2 Systems Word
 Problems worksheet

Tomorrow – More practice with word
 problems and solving systems by elimination
MINI-QUIZ TOMORROW
  Solving Systems by Elimination (2 Problems)
  1 word problem

								
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