Question

X^-9*x^-2 a 1/x^18 b 1/x^11 c x^18 d x^11

Answer 1

Exponent rule : a^-x = 1/a^x

x^-9 * x^-2 = 
1/x^9 * 1/x^2 = (when multiplying exponents with same base, add exponents)
1/x^(9 + 2) =
1/x^11