The rate of change is the ratio between the x and y (or input and output) values in a relationship. Another term for the rate of change for proportional relationships is the constant of proportionality.

If the rate of change is yx, then so is the constant of proportionality. To simplify things, we set yx=k, where k represents the constant of proportionality.

If you solve a yx=k equation for y, (like this: y=kx), it is called a direct variation equation. In a direct variation equation, y varies directly with x. When x increases or decreases, y also increases or decreases by the same proportion.

To find y in a direct variation equation, multiply x by the constant of proportionality, k.

For example: Given the relationship y=7x, the constant of proportionality k=7, so if x=3, then y=3×7 or 21.

Given the same relationship, if x=7, then y=7×7, or 49.

Step-by-step explanation:

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2 years ago

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Sarah swam four-fifths of a lap in the morning and seven-fifteenths of a lap in the evening. How much farther did Sarah swim in

ryzh [129]

1/3 is the answer
Hope this is correct

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2 years ago