OG详解-OG7 数学2 Q9

Choice C is correct. Since x is a common factor of each term in the given expression, the given expression can be rewritten as x(23x² +2^x+9).
Choice A is incorrect. This expression is equivalent to 23x³ +46x² +207x. Choice B is incorrect. This expression is equivalent to 207x⁴ +18x³ +9x.   Choice D is incorrect. This expression is equivalent to 34x³ +34x² +34x.