What do you remember Substitution vs Elimination Example

�What do you remember? Substitution vs. Elimination

Example 1 Substitution elimination? or

Substitution or elimination? Example 2: 3 x + 2 y = 12 x – 2 y = 6

Example 3 Substitution Elimination? or

Example 4 Substitution Elimination? or

Example 5 Substitution Elimination? or 4 x + 3 y =4 8 x -12 y = -1

Example 6 Substitution or Elimination? 9 x + 6 y = 15 23= -6 x – 7 y

�Create �Get an an equation from another person. You now have a system of equations. �Solve your system by graphing, substitution and elimination. �Check your answers using the graphing calculators. Do NOW!!!

Lesson 1. f continued: solve word problems using systems of equations At the end of this lesson you will be able to… � Set up a system of equations to model a real world situation. � Find the solution to a real world situation by solving a system of equations

Example 1: The sum of two numbers is 90. Their difference is 18. Find both the numbers. Define the variables. Set up two separate equations Solve the system using substitution or elimination 4. CHECK YOUR ANSWER!!! 5. WRITE A SENTENCE!!! 1. 2. 3.

Example 2: The number of girls at Sky High School is 60 greater than the number of boys. If there are 1250 students all together, how many girls are there? Define the variables. Set up two separate equations Solve the system using substitution or elimination 4. CHECK YOUR ANSWER!!! 5. WRITE A SENTENCE!!! 1. 2. 3.

Example 3: A group of students eat lunch together everyday. One day two of them have hamburgers and five have hot dogs. The bill came to $8. 00. The next day five students have hamburgers and two have hot dogs. The bill that day was $9. 50. What is the price of a hamburger? 1. 2. 3. 4. 5. Define the variables. Set up two separate equations Solve the system using substitution or elimination CHECK YOUR ANSWER!!! WRITE A SENTENCE!!!

Example 4: � The sum of three numbers is -4. The second number decreased by the third is equal to the first. The sum of the first and second number is 5. Find the three numbers. 1. Define the variables. 2. Set up three separate equations 3. Solve the system using substitution 4. CHECK YOUR ANSWER!!! 5. WRITE A SENTENCE!!! or elimination

Class Work: Complete your ticket out the door worksheet.

Homework: �do the problems exactly the way we did in the notes.