Bunuel wrote:

y = 248 - 398x

Which of the following values of x gives the greatest value of y in the equation above?

(A) 200

(B) 100

(C) 0.5

(D) 0

(E) -1

We see that if x is negative, rather than subtracting 398x from 248, we are summing the values. Thus, when x is -1, we can get the largest value of y.

Alternate solution:

We see that the given equation is a line with a negative slope (i.e., a line that is going down from left to right). Thus, the smaller the x-value, the larger the y-value. Therefore, when x is the smallest, y will be the largest. The smallest x-value given is -1 and it will yield the maximum y-value.

Answer: E

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Jeffery Miller

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