Lesson 3-4

Solving Multi-Step Equations

Definition

• Working Backward- work the axiom of order backwards.

Examples• Solve each problem by working backwards.

– A) A number is multiplied by seven, and then the product is added to 13. The result is 55. What is the number?

– B) A bacteria population triples in number each day. If there are 2,187,000 bacteria on the seventh day, how many bacteria were there on the first day?

Definition

• Multi-step equations- an equation with more than one type of operation.

Solve. Then check your solution.

37135 a) =−q 11912 b) −=−s

23

8 c) −=

−+r

Write an equation for the problem below. Then solve the equation.

• Eight more than five times a number is negative 62.

Definitions

• Consecutive integers- are integers in counting order, such as 7, 8, and 9.

• Number theory- The study of numbers and the relationship between them.

• Find three consecutive odd integers whose sum is 57.

• Find three consecutive integers whose sum is 42.