Answer:
a^8 ÷ b^12
Step-by-step explanation:
a^-5 · b^-4 / a^-13 · b^8
when dividing exponents with the same bases, subtract the exponents
a^8 · b^-12
do not leave a negative exponent; put it into the denominator and it becomes positive
b^-12 = 1 /b^12
