McGraw Hill Glencoe Algebra 1 Texas, 2016
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McGraw Hill Glencoe Algebra 1 Texas, 2016 View details
1. Inverse Variation
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Exercise 1 Page 679

What does plotting the points on a coordinate plane suggest?

Variation: Direct
Explanation: The data in the table can be represented by the equation y=2x.

Practice makes perfect

We want to determine whether the relationship between the variables in the given table represents a direct variation or an inverse variation. Let's see what happens if we plot the points on a coordinate plane.

We can see that this might be a direct variation relationship. y=kx or k=y/x In the above formulas, k is the constant of variation and k cannot equal 0. Let's test to see if the quotient of y and x is constant for the given values.

x y y/x
1 2 2/1 = 2
4 8 8/4 = 2
8 16 16/8 = 2
12 24 24/12 = 2

The quotient of each pair is constant and it is equal to 2. Therefore, it is a direct variation y=2x.