7th Grade Math

Multi-Step Equations

PART A BCD

Multi-Part

Lesson 3

Get ConnectED

GLE 0706.3.7

Use mathematical models

involving linear equations

to analyze real-world

phenomena. SPI 0706.3.8

Solve contextual problems

involving two-step linear

equations. Also addresses

GLE 0706.1.4, GLE 0706.1.8,

GLE 0706.3.8.

228 Equations and Inequalities

Solve Two-Step Equations

with Bar Diagrams

SPORTS Two identical basketballs and five

identical tennis balls weigh a total of

52 ounces. Each tennis ball weighs 2 ounces.

What is the weight of a basketball?

What do you need to find? the weight of a basketball

Draw a bar diagram that represents the two basketballs

and five tennis balls. Label the parts.

Write an equation from the bar diagram. Let x represent

the weight of a basketball.

2 x + 10 = 52

Use the work backward strategy to find the weight of

the basketballs. Since 2x + 10 = 52, 2x = 52 - 10 or

42, and 42 ÷ 2 = 21.

Check 2 · 21 + 10 = 52 

The weight of one basketball is 21 ounces.

the Results

1. Suppose there were 10 identical tennis balls and 3 identical soccer
   balls that had a total weight of 53 ounces. You want to find the
   weight of one soccer ball. How would the above equation change?


2. BAR DIAGRAM Ryan is saving money to buy a skateboard
   that costs $85. He has already saved $40 and plans to save the
   same amount each week for three weeks. Draw a bar diagram and
   write an equation to find how much he should save each week.
   Then solve the equation.

Main Idea

Write and solve

two-step equations

using bar diagrams.

52 oz

?? 2 oz 2 oz 2 oz 2 oz 2 oz

basketball basketball tennis tennis tennis tennis tennis

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