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Algebra / Linear functions Difficulty: Easy
xx f(x)f(x)
00 2929
11 3232
22 3535

For the linear function f , the table shows three values of x and their corresponding values of f(x). Which equation defines f(x)?

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Explanation

Choice A is correct. An equation that defines a linear function f can be written in the form fx=mx+b, where m and b are constants. It's given in the table that when x = 0 , fx=29. Substituting 0 for x and 29 for fx in the equation fx=mx+b yields 29=m0+b, or 29 = b . Substituting 29 for b in the equation fx=mx+b yields fx=mx+29. It's also given in the table that when x = 1 fx=32. Substituting 1 for x and 32 for fx in the equation fx=mx+29 yields 32=m1+29, or 32 = m + 29 . Subtracting 29 from both sides of this equation yields 3 = m . Substituting 3 for m in the equation fx=mx+29 yields fx=3x+29.

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

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

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