1. BEFORE: August 31, What will happen if you add or subtract an equal amount of weight on both sides of the scales?
Solving equations is like balancing scales, we must always keep the sides equal.
ATTENTION
Please answer in a complete sentence.

2. DURING: Solving equations by adding and subtracting
Learning Target:
I can solve one-step equations using addition and subtraction.

3. What does solving an equation mean?
It means to find all values of a variable that make an equation true. Solving one-step equation is as straightforward as it sounds. You will only need to perform one step in order to solve the equation.

4. With any math there are new vocabulary words and rules we must follow
With any math there are new vocabulary words and rules we must follow. Let’s look at some of the new terms and rules before we move on.

5. Equation – a mathematical sentence that shows two expressions are equal. Solve – to find the answer or solution. Solution – the value that makes an equation true. Inverse operations – operations that “undo” each other; addition and subtraction, multiplication and division. Isolate the variable – to get the variable on one side of an equation or inequality by itself in order to solve. Open sentence – an equation that contains at least one variable.

6. Addition Property of Equality – states you can add the same amount to both sides of an equation and the equation remains true = = = 9 ? true Subtraction Property of Equality – states you can subtract the same amount from both sides of an equation and the equation remains true = – 3 = 11 – = 8 ? true

7. “I DO” Determining Whether a Number is a Solution of an Equation
Determine which value of x is a solution of the equation.
x + 8 = 15; x = 5, 7, or 23

8. “WE DO” Determining Whether a Number is a Solution of an Equation
Determine which value of x is a solution of the equation.
x – 10 = 4; x = 6, 14, or 26
b + 2/3 = 2; b = 2/3, 3/2, or 4/3

9. “YOU DO” Determining Whether a Number is a Solution of an Equation
Determine which value of x is a solution of the equation.
-12 = c + 3; c= -15, -4, or 15
d + ¼ = 2; d= 4/7, 7/4, or 8

10. Procedure
Isolate the variable by performing the inverse operation on that variable.
The inverse of subtraction is adding. The inverse of addition is subtracting
Perform the same operation on the side of the equal sign that does not have a variable.

11. “I DO”
w – 3 = 9
It is very important to write all the steps and check your answer each time you solve an equation

12. “WE DO”
k – 8 = -7
t + 5 = -25
2.8 = z + 0.5
3/8 = t – 1/8

13. “YOU DO”
20 = v
n = 3
s – 5 = 3
17 = w – 4

14. “I DO” Problem Solving Application Jan and Alex are arguing over who gets to play a board game. If Jan, on the right, pulls with a force of 14 N, what force is Alex exerting on the game if the net force is 3 N?
3=f+14; f= -11

15. “WE DO” Problem Solving Application Frankie and Carol are playing tug of war using a rope. If Frankie, on the right, pulls with a force of 7 N, what force is Carol exerting on the game if the net force is 4 N?
4=f+7; f=-3

16. “YOU DO” Problem Solving Application 1
“YOU DO” Problem Solving Application 1. The price of your favorite cereal is now $4.25. In prior weeks the price was $3.69. Write and solve an equation to find n, the increase in the price of the cereal.
n = 4.25; n= $0.56

17. “YOU DO”
2. Luis depostied $500 into this bank account. He now has $4,732. Write and solve an equation to find how much was in his account before the deposit. Show that your answer is reasonable.

18. “WE DO” Write an equation to represent each relationship
“WE DO” Write an equation to represent each relationship. Then solve the equation.
1. Ten less than a number is equal to 12.
2. A number decrease by 13 is equal to 7.
3. Eight more than a number is 16.

19. “YOU DO” Write an equation to represent each relationship
“YOU DO” Write an equation to represent each relationship. Then solve the equation.
1. The sum of 5 and a number is 6.
2. Two less than a number is -5.
3. The difference of a number and 4 is 9.

20. AFTER: Error Analysis Here are two possible solutions to x = Which is incorrect? Explain the error.

21. Practice Problems Page 20 #22-48 even, 59