1. Because b has a negative exponent you use the negative exponent rule which changes b^-2 to A fraction with a positive exponent: 1/b^2
This moves b^2 to be the denominator.
The answer would be 3a^4c^3/b^2
2. Replace a with 5, so you get -5^-2
Using the negative exponent rule this becomes a fraction -1/-5^2 which simplifies to -1/25
