OG详解-OG4 数学1 Q8

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