OG详解-OG2 数学1 Q22

Choice B is correct. It’s given that  f(x)= (x +6)(x +5)(x -4) and y = f (x)-3 . Substituting (x +6)(x +5)(x -4) for f(x) in the equation y = f (x)-3 yields y = (x +6)(x +5)(x -4)-3. Substituting -6  for x in this equation yields y = (-6 +6)(-6 +5)(-6-4)-3, or y =-3. Substituting -5  for x  in the equation y = (x +6)(x +5)(x -4)-3 yields y = (-5 +6)(-5 +5)(-5-4)-3, or y =-3. Substituting 4 for x  in the equation y = (x +6)(x +5)(x -4)-3 yields y = (4 +6)(4 +5)(4 -4)-3 , or y =-3. Therefore, when x =-6 then y =-3, when x =-5 then y =-3, and when x = 4  then y =-3. Thus, the table of values in choice B represents y = f (x)-3.