use only positive exponents in answer

Question

2u^-9 x^-7 y^-4 * 7u^9 * 3y^-1 x

Answer 1

2U^-9X^-7Y^-4 * 7U^9 * 3XY^-1.

42U^0X^-6Y^-5=

42 / X^6Y^5.