2. Solving for the Unknown: A How-to Approach for Solving Equations
Chapter 5
Solving for the Unknown: A How-to Approach for Solving Equations
McGraw-Hill/Irwin
Copyright © 2003 by The McGraw-Hill Companies, Inc. All rights reserved.

3. Solving for the Unknown: A how-to Approach for Solving Equations#5
Solving for the Unknown: A how-to Approach for Solving Equations
Learning Unit Objectives
LU5.1
Solving Equations for the Unknown
Explain the basic procedures used to solve equations for the unknown
List the five rules and the mechanical steps used to solve for the unknown in seven situations; know how to check the answers

4. Solving for the Unknown: A how-to Approach for Solving Equations#5
Solving for the Unknown: A how-to Approach for Solving Equations
Learning Unit Objectives
LU5.2
Solving Word Problems for the Unknown
List the steps for solving word problems
Complete blueprint aids to solve word problems; check the solutions

5. Solving Equations for the Unknown
Equality in equations
A + 8 58
Left side of equation
Right side of equation

6. Solving for the Unknown Rule
Whatever you do to one side of an equation, you must do to the other side.

7. Opposite Process Rule
A + 8 = 58
A = 50

8. Equation Equality Rule
Y = 7

9. ( ) Multiple Process Rule X + 5 = 50 9 -5 -5 X = 45 X = 45(9) X = 405
X = 45
X = 45(9)
X = 405 ( )
(9)

10. Parentheses Rule
2(N - 6) = 8
2N - 12 = 8
2N = 20
N = 10

11. Like Unknown Rule
3Y - Y = 52
2Y = 52
Y = 26

12. Solving Word Problems for Unknowns
1) Read the entire Problem
2) Ask: “What is the problem looking for
3) Let a variable represent the unknown
4) Visualize the relationship between the unknowns and variables. Then set up equation
Y = Computers
5) Check your results
4Y + Y = 600

13. Solving Word Problems for the Unknown

14. Solving Word Problems for the Unknown
Barbie and Ken sell cars at the Auto World. In April they sold 15 cars. Barbie sold twice as many cars as Ken. How many cars did each sell?
Cars Sold
Barbie C C
Ken C C 15
2C + C = 15
3C = 15
C = 5
Barbie - 10 Cars
Ken 5 Cars