When dividing by a negative the sign changes to the opposite.
Given the following functions below,

Factorising the denominators of both functions,
Factorising the denominator of f(x),

Factorising the denominator of g(x),

Multiplying both functions,
Answer: the answer is 7
Step-by-step explanation: the lowest number is 3 and the biggest one is 10 so you substract 10-3 and you get 7