Houghton Mifflin Harcourt Algebra 1, 2015
HM
Houghton Mifflin Harcourt Algebra 1, 2015 View details
2. Creating and Solving Equations
Continue to next subchapter

Exercise 11 Page 51

Construct a table in the context of a problem.

A table is useful to organize information and recognize relationships.

Practice makes perfect

A table is useful to organize information and recognize relationships. Let's see an example.

Example

Janice, Tia, and Amy collect marbles. Janice has twice as marbles as Tia. Amy has three more marbles than Tia. Next week they will buy three marbles each. The number of marbles Janice will have is the same as the number of marbles Amy will have. Find the number of marbles each of the girls has.

Using a table

Let's start by writing an expression for the number of marbles they have. Let x be the number of marbles Tia has.

Verbal Phrase Algebraic Expression
Janice Twice as Tia 2 x
Tia - x
Amy Three more than Tia 3 + x

Considering they will have three more marbles each, construct a table to organize the information.

Number of Marbles They Currently Have Number of Marbles They Will Have Next Week
Janice 2x 2x + 3
Tia x x + 3
Amy 3+x 3+x + 3

Now we have expressions for the number of marbles the three girls will have next week.

Setting and solving an equation

The number of marbles Janice will have is the same as the number of marbles Amy will have. 2x+3=3+x+3 We will sove the above equation to find the value of x. Let's start by simplifying the right-hand side.
2x+3=3+x+3
2x+3=x+6
2x+3-3=x+6-3
2x=x+3
2x-x=x+3-x
x=3
We found that x=3.

Giving the answer in the context of the problem

In the context of the problem, x is the number of marbles Tia has. Thus, she has 3 marbles. Since Janice has twice as marbles as Tia, she has 6 marbles. Since Amy has three more than Tia, she also has 6 marbles. Tia:& 3marbles Janice:& 6marbles Amy:& 6marbles