Big Ideas Math: Modeling Real Life, Grade 8
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Big Ideas Math: Modeling Real Life, Grade 8 View details
3. Graphing Proportional Relationships
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Exercise 13 Page 159

When two quantities x and y are proportional, the relationship can be represented by the equation y=mx.

No, see solution.

Practice makes perfect

Consider the given ratio table.

x 2 5 8 10
y 4 8 13 23

The value of x and its corresponding value of y represents an ordered pair that can be plotted in a coordinate plane. Let's plot the ordered pairs!

We want to find if x and y are in a proportional relationship. To do so, remember when two quantities are proportional, the relationship can be represented by the following equation. y=mx Here, m is the constant of proportionality. The graph of this equation is a line with a slope m that passes through the origin. Notice that we cannot draw a straight line that passes through all of the ordered pairs. Therefore, x and y are not in a proportional relationship.

Extra

Linear Equations

A linear equation is an equation whose graph is a line.

This type of equation contains at least one linear term and any number of constants. Let's see a few examples! & y=2x+1, & 3x=6 +3, & 2y+x=4 For those of you who are interested in learning more about the different types of linear equations and their graphs, you can read more about them on the following pages.