Fill in the blanks to make the statements true:

x and y are said to vary directly with each other if for some positive number k, ……… = k.

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When two quantities x and y are in ………. Proportion or vary ………… they are written as x ∝ 1/y.

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Both x and y are said to vary ……… with each other if for some positive number k, xy = k.

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Two quantities are said to vary ……………. With each other if they increase (decrease) together in such a manner that the ratio of their corresponding values remains constant.

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Two quantities are said to vary ……………. with each other if an increase in one causes a decrease in the other in such a manner that the product of their corresponding values remains constant.