Title: Lesson 1-1
Author: Unknown User
Company: DellComputerCorporation

Lesson 4-2

Example 1 Solve an Addition Equation
Solve x + 7 = 10.  Check your solution.
	
x + 7 = 10			Write the equation.
   - 7  =  - 7			Subtract 7 from each side.
x       =   3			Simplify.

Check		x + 7 = 10	Write the equation.	
	            3 + 7 = 10	Replace x with 3.
	                10 = 10	The sentence is true.

The solution is 3.

Example 1 Solve an Addition Equation
Solve x + 2 = 8.  Check your solution.
	
x + 2 =    8			Write the equation.
   - 2  =  - 2			Subtract 2 from each side.
x       =    6			Simplify.

Check		x + 2 = 8	Write the equation.	
	            6 + 2 = 8	Replace x with 6.
	                  8 = 8	The sentence is true.

The solution is 6.

Example 3  Use an Equation to Solve a Problem
CONSTRUCTION  Two types of tiles are being used in a construction project.  A slate tile measures 12 inches in length and is 3 inches longer than a granite tile.  How long is the granite tile?

Words		A slate tile is 3 inches longer than a granite tile.
Variable	Let x = the length of the granite tile.
Equation	12 = 3 + x

 12 =   3 + x			Write the equation.
- 3  = - 3			Subtract 3 from each side.
  9  =        x			Simplify.

The granite tile is 9 inches long.

Example 4 Solve a Subtraction Equation
Solve 4 = p – 5.  Check your solution.

    4 = p – 5		Write the equation. 
+ 5 =    + 5		Add 5 to each side.
   9 = p			Simplify.

Check   4 = p – 5	Write the original equation.
	 4   9 – 5	Replace p with 9.	
	 4 =  4	  	This sentence is true.

The solution is 9.

Example 4 Use an Equation to Solve a Problem
GARDENING   A tomato plant grew 10 centimeters in four weeks. It grew 1 centimeter, 2 centimeters, and 4 centimeters in the first three weeks after it was planted.  How much did the plant grow in the fourth week?  

Words		The sum of the growth for all four weeks is 10 centimeters.

Variable	Let g represent the growth during the fourth week.

		  growth for the 	    growth for the	
		first three weeks	     fourth week	       total growth	
Equation	   1 + 2 + 4	      +                g		=             10

1 + 2 + 4 + g = 10	Write the equation.	
            7 + g = 10	1 + 2 + 4 = 7
          - 7       = - 7	Subtract 7 from each side.
	      g =  3	Simplify.	

Check   You can check the solution by adding.
	 1 + 2 + 4 + 3 = 10  

The tomato plant grew 3 centimeters during the fourth week.