OG详解-OG2 数学2 Q5

Choice B is correct. Applying the commutative property of multiplication, the expression (m⁴q⁴z^-1)(mq⁵z³ ) can be rewritten as  (m⁴m)(q⁴q⁵ )(z^-1z³ ). For positive values of x , (x^a )(x^b )= x^a+b. Therefore, the expression (m⁴m)(q⁴q⁵ )(z^-1z³ ) can be rewritten as  (m⁴⁺¹)(q⁴⁺⁵ )(z^-1+3 ), or  m⁵q⁹z² .
Choice A is incorrect and may result from multiplying, not adding, the exponents. Choice C is incorrect and may result from conceptual or calculation errors. Choice D is incorrect and may result from conceptual or calculation errors.