Because 11 is common to both terms, multiply means add the exponents: 11^(-5+(-3))=11^(-5-3) or 11^-(5+3)=11^-8.
Same applies to -2: -(-2)^(0+3-4-3) (because divide means subtract just as multiply means add). -(-2)^(-4) is the result of combining the exponents. Even exponents turn the minus in front of the 2 into plus: -(2)^(-4). Minus in an exponent means reciprocal: -1/2^4=-1/16, because 2 to the power 4 is 16. Note how the leading minus sign stays all the way through.