OG详解-OG7 数学2 Q23

Choice C is correct. It’s given that g(c+7)=c​4​. Therefore, for the given linear function g, when x = c+7, g(x) = c​4​. Substituting c+7 for x and c​4​ for g(x) in g(x) = b - 15x yields  c​4​= b-15(c+7).  Applying the distributive property to the right-hand side of this equation yields c​4​= b-15c-105. Adding 15c to both sides of this equation yieldsc​4​ +15c = b-105. Adding 105 to both sides of this equation yields  c​4​+15c+105 = b, or  61​c4​ +105 = b. Therefore, the expression that represents the value of b is 61​c4​+ 105.
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 D is incorrect and may result from conceptual or calculation errors.