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To solve this problem, you need to remember that every time two variables are directly proportional to each other, the equation that models the relationship is: .

The first step in solving this equation is to find the value of *k*. To find *k* we have to divide both sides of the equation by *x,* giving us . Plugging in *-25* for *y* and *-5* for *x, *finds that *k = 5*.

Using the value of *k* we can find the value of *y* when *x = 1.* Multiplying *5*, the value of *k,* and *1,* the value of *x*, together finds that *y = 5,* which is C.

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