Simplify each expression. Write answers without negative exponents. Assume all variables represent nonzero real numbers. x¹²/x⁸

Simplify each expression. Write answers without negative exponents. Assume all variables represent nonzero real numbers. r⁷/r¹⁰

Write each expression without negative exponents, and evaluate if possible. Assume all variables represent nonzero real numbers. (-4)^-3

Simplify each expression. Write answers without negative exponents. Assume all variables represent nonzero real numbers. (5x)^-2(5x³)^-3/(5^-2x^-3)^-3

Perform the indicated operation, and write each answer in lowest terms. 2x/5 ∙ 10/x²

Perform the indicated operation, and write each answer in lowest terms. y³/8 ÷ y/4

Perform the indicated operation, and write each answer in lowest terms. (4/x-y) - (9/x-y)

Perform the indicated operation, and write each answer in lowest terms. 2x/5 + x/4