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.
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
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
Solving Equations for the Unknown Equality in equations A + 8 58 Left side of equation Right side of equation
Solving for the Unknown Rule Whatever you do to one side of an equation, you must do to the other side.
Opposite Process Rule A + 8 = 58 - 8 - 8 A = 50
Equation Equality Rule 4 4 Y = 7
( ) Multiple Process Rule X + 5 = 50 9 -5 -5 X = 45 X = 45(9) X = 405 -5 -5 X = 45 X = 45(9) X = 405 ( ) (9)
Parentheses Rule 2(N - 6) = 8 2N - 12 = 8 +12 +12 2N = 20 2 2 N = 10
Like Unknown Rule 3Y - Y = 52 2Y = 52 2 2 Y = 26
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
Solving Word Problems for the Unknown
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 2C 2C Ken C +C 15 2C + C = 15 3C = 15 C = 5 Barbie - 10 Cars Ken 5 Cars