Simplify the expression. Write your answer using only positive exponents.

Explain as well.

1. (8x)^3*8^-4
2. 2x^-5*y^-3
3. (4x^4y^-3)^-2
4. 1/(3x)^-2

2 answers

1. (8x)^3*8^-4 = 8^3*x^3/8^4 = x^3/8

4. 1/(3x)^-2 = (3x)^2 = 9x^2

Now you try the others. Get rid of negative exponents by moving those terms from numerator to denominator, or vice versa.
I see that Reiny already answered all the questions for you, when you posted earlier.