Question

A car manufacturer is reducing the number of incidents with the transmission by issuing a voluntary recall. During week 2 of the recall, the manufacturer fixed 192 cars. In week 4, the manufacturer fixed 184 cars. Assume that the reduction in the number of cars each week is linear. Write an equation in function form to show the number of cars seen each week at the mechanic.

A.) f(x) = 4x + 200

B.) f(x) = 2x + 192

C.) f(x) = −4x + 200

D.) f(x) = −2x + 192

Answer 1

c.f(x)= -4x+200

Explanation:

i took the test

Answer 2

C.) f(x) = −4x + 200

Explanation:

Since the number is decreasing, you know the slope will be negative, eliminating the first two choices. The equation in the last choice does not match the given data, so it can be eliminated.

In other words, the easiest way to solve this problem is to check the answers against the given data.

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If you want to write the equation from scratch, you need to find the slope. That is ...

(change in number of cars)/(change in weeks) = (184 -192)/(4 -2) = -8/2 = -4

This matches only one answer, but you can go on to finish the equation by starting with point-slope form:

y -192 = -4(x -2)

y = -4x +8 +192 . . . . add 192, eliminate parentheses

y = -4x + 200 . . . . matches choice C.)