Upcoming SlideShare
×

# Solving equations

7,890 views

Published on

1 Like
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
• Be the first to comment

Views
Total views
7,890
On SlideShare
0
From Embeds
0
Number of Embeds
4,462
Actions
Shares
0
112
0
Likes
1
Embeds 0
No embeds

No notes for slide
• Poll #1: The 3 that is in front of the x is a (a) coefficient, (b) constant, (c) variable, or (d) fraction. Poll #2: The 36 is a (a) coefficient, (b) constant, (c) variable, or (d) fraction. Poll #3: The x is a (a) coefficient, (b) constant, (c) variable, or (d) fraction. Discuss the -1 coefficient on the RHS of the equation. Slide in labels after polls are completed. Discuss equals sign to transition to next slide.
• Have students brainstorm scenarios in which trial and error would be tedious.
• Is there only one way to solve an equation? Do the steps have to happen in a specific order?
• ### Solving equations

1. 1. Solving Equations
2. 2. __ __ ____ _ Solving Equations Vocabulary 1) open sentence 2) equation 3) solution <ul><li>Translate verbal expressions into algebraic expression and equations and vice versa. </li></ul><ul><li>Solve equations using the properties of equality. </li></ul>
3. 3. Solving Equations A mathematical sentence (expression) containing one or more variables is called an open sentence . A mathematical sentence stating that two mathematical expressions are equal is called an _________. equation Open sentences are neither true nor false until the variables have been replaced by numbers. Each replacement that results in a true statement is called a ________ of the open sentence. solution
4. 4. To solve equations, we can use properties of equality. Some of these equivalence relations are listed in the following table. Reflexive Symmetric Transitive Substitution For any real number a , a = a , For all real numbers a and b , If a = b, then For all real numbers a , b , and c . If a = b, and b = c, then If a = b, then a may be replaced by b and b may be replaced by a. b = a a = c – 5 + y = – 5 + y If 3 = 5x – 6, then 5x – 6 = 3 If 2x + 1 = 7 and 7 = 5x – 8 then, 2x + 1 = 5x – 8 If (4 + 5) m = 18 then 9m = 18 Solving Equations Properties of Equality Property Symbol Example
5. 5. Sometimes an equation can be solved by adding the same number to each side or by subtracting the same number from each side or by multiplying or dividing each side by the same number. Addition and Subtraction Properties of Equality For any real numbers a , b , and c , if a = b, then a = b + c + c a = b - c - c Example: If x – 4 = 5, then x – 4 = 5 + 4 + 4 If n + 3 = –11, then n + 3 = –11 – 3 – 3 Solving Equations
6. 6. Sometimes an equation can be solved by adding the same number to each side or by subtracting the same number from each side or by multiplying or dividing each side by the same number. Multiplication and Division Properties of Equality For any real numbers a , b , and c , if a = b, then a = b · c · c a = b Example: 4 4 Solving Equations c c - 3 -3
7. 7. <ul><li>What will we discuss? </li></ul><ul><ul><li>What are the parts of an equation </li></ul></ul><ul><ul><li>What does it mean to solve an equation </li></ul></ul><ul><ul><li>How do we use inverse operations to solve equations </li></ul></ul><ul><ul><li>How to solve simple and complex equations </li></ul></ul>Chapter 5: Solving Equations
8. 8. What Does it Mean to Solve an Equation? <ul><li>To solve an equation means to find every number that makes the equation true. </li></ul><ul><li>We do this by adding or subtracting to each side of the equation … but always keep it balanced! </li></ul>
9. 9. What are the parts of an equation? <ul><li>Let’s first take a look at an equation and identify its parts </li></ul>Coefficient Constant Variable
10. 10. So do we just use trial and error to find the right value? <ul><li>No. </li></ul><ul><li>We can use inverse operations to isolate, or solve for, the variable’s value. </li></ul><ul><li>Inverse operations? Think about it … </li></ul><ul><li>The inverse operation of addition is subtraction . And the inverse operation of multiplication is division . </li></ul>
11. 11. Solving 1 Step Equations How much does the suitcase weigh in terms of blocks? B=Blocks S=Suitcase Equation: 6B + S = 9B -6B -6B 3B S = What is the weight of the suitcase if each block has a weight of 2lbs. ? S = 3 (2) = 6 lbs.
12. 12. So how do we solve equations with inverse operations? <ul><li>Let’s take a look at a simple equation </li></ul>Step 1: - 13 Answer: - 13 Now that we have solved the equation, let’s check the solution:
13. 13. So how do we solve equations with inverse operations? <ul><li>Let’s take a look at a simple equation </li></ul>Step 1: + 5 Answer: + 5 Now that we have solved the equation, let’s check the solution:
14. 14. So how do we solve equations with inverse operations? <ul><li>Let’s take a look at a simple equation </li></ul>Step 1: Step 2: 25 Answer: 25 Now that we have solved the equation, let’s check the solution:
15. 15. So how do we solve equations with inverse operations? <ul><li>Let’s take a look at a simple equation </li></ul>Step 1: Step 2: (16) Answer: (16) Now that we have solved the equation, let’s check the solution:
16. 16. 1 Step Equation X + 11 = 9 X - 37 = 52 3X = 72 -11 -11 X = -2 3 3 X = 24 1 1 20 + h = 41 17 - s = 27 This is the same as -1S=10
17. 17. 1 Step Equations Continued… 6X = 42 P = 6 6 1 X=7 or x = 7 1 1 Cross Multiply Multiply by the reciprocal of 2/5 2 5 3 4
18. 18. Multi Step Equations Solve: 8m – 10 = 36 8m – 10 = 36 8m = 46 8 8 m = + 10 + 10
19. 19. Multi Step Equations 5x  2 = x + 4 Solve: 5x  2 = x + 4 Notice that there are variables on both sides 5x = x + 6 Get rid of the -2 on the left side Simplify 5x = x + 6 Get rid of the x on the right side 4x = 6 Get rid of the coefficient of x 4 4 x = Simplify Simplify + 2 + 2 – x – x
20. 20. Solving a Proportion <ul><li>Solve the proportion below </li></ul>12 12
21. 21. Solving a Proportion <ul><li>Solve the proportion below </li></ul>52 52
22. 22. Checking the Solution to a Proportion <ul><li>Let’s check the solution to the proportion we solved on the last slide </li></ul>2
23. 23. Using Proportions to Solve Problems <ul><li>You get 46 miles to a gallon of gas. How far can you go on 16 gallons of gas? </li></ul>
24. 24. Multi-step Solutions <ul><li>Let’s take a look at our original equation </li></ul>Step 1: -12 -12 Step 2: +x +x Step 3: 4 4 Answer:
25. 25. Multi-step Solutions (involving distribution) <ul><li>Consider the following equation </li></ul>Step 1: Step 2: Step 3: Answer: +30 +30 6 6
26. 26. Finding Variations of Formulas <ul><li>Solve the formula for r . </li></ul>