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Algebra / Linear functions Difficulty: Medium

The function f is defined by f(x)=7x-84. What is the x-intercept of the graph of y=f(x) in the xy-plane?

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Explanation

Choice D is correct. The given function f is a linear function. Therefore, the graph of y=fx in the xy-plane has one x-intercept at the point k,0, where k is a constant. Substituting 0 for fx and k for x in the given function yields 0=7k-84. Adding 84 to both sides of this equation yields 84=7k. Dividing both sides of this equation by 7 yields 12=k. Therefore, the x-intercept of the graph of y=fx in the xy-plane is 12,0.

Choice A is incorrect and may result from conceptual or calculation errors.

Choice B is incorrect and may result from conceptual or calculation errors.

Choice C is incorrect and may result from conceptual or calculation errors.