7.2 notes 7.2 solving systems by substitution
TRANSCRIPT
7.2 Solving Systems by
Substitution Warm Up and Discuss with your Partner 1) Solve the system of Equations by Graphing: 2) Solve the system of Equations by Graphing:
2y x 7
3x 4y 8
2x 3y 9
y x 7
Think and Discuss: Did you experience any frustrations with the problems above? Describe in a couple sentences below:
Alternatives to Graphing: SUBSTITUTION METHOD! Think and Discuss: What does the word SUBSTITUTE mean?
Solve the following using the Substitution Method.
y x 7
x 4y 8
2x 3y 9
y x 7
7.2 Notes
Steps for SUBSTITUTION METHOD!
1. Decide which variable is easiest to _____________________________.
2. ____________________________ for that variable.
3. ____________________________ the expression from step 2 back into the OTHER equation.
4. Use the found value of one variable to find the value of the other variable.
5. _______________________ both values by plugging them back into the original equation.
Let’s Practice Substitution
Ex. 1
x 2y 7
x y 23
Ex. 2
7x 2y 24
4x y 8
Ex. 3
y 2x 19
y x 7
Ex. 4
y 2x
y 3x 2
Ex. 6 Gina went shopping for holiday presents. She bought boxes of chocolates and boxes of ornaments for her coworkers. Boxes of chocolate cost $8 each and boxes of ornaments cost $6 each. She buys a total of 22 boxes and spends $152. How many boxes of chocolates and how many boxes of ornaments does she buy?