The value of y varies directly with x. If x= 3, then y = 13.
What is the value of x when y = 39?

9514 1404 393

  9

Step-by-step explanation:

"Varies directly" means the values change by the same factor. Here, we have y increasing from 13 to 39, by a factor of 3.

Since x varies directly as y, it, too, will increase by a factor of 3:

  x = 3·3

  x = 9

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Alternate solution

"Varies directly" is another way to say the values are proportional. Then the new value of x can be found from ...

  x-value/y-value = 3/13 = x/39

Multiplying by 39 gives ...

  x = 39(3/13) = 3·3

  x = 9

they can both be solutions depends on the equation

step-by-step explanation:

what is the equation? ?