Lesson 1-10

Example 1 Solve a Multiplication Equation
Solve 25x = 300.
 
 25x = 300		Write the equation.
		Divide each side of the equation by 25.
    1x = 12		25  25 = 1 and 300  25 = 12
      x = 12		Identity Property; 1x = x

Example 2 Solve a Division Equation
Solve .
       		Write the equation.
	Multiply each side by –4.
            c = 20		–5 ∙ (–4) = 20

Example 3 Use an Equation to Solve a Problem
WILDLIFE A female elephant grows to be 40 times its weight at birth. If an adult female elephant weighs 8,000 pounds, how much does a baby elephant weigh?

Words		The weight of an adult female elephant is 40 times its weight at birth.
Variable	Let w = the weight of a baby female elephant.
Equation	8,000 = 40w

  8,000 = 40w		Write the equation.
 = 		Divide each side by 40.
     200 = w		8,000  40 = 200

The weight of a baby elephant is 200 pounds.