Please help.

Simplify each expression. Your answer should contain only positive exponents.

(3x^4·y^5)^2

Describe all the numbers that when rounded to the nearest thousand are 645,000

Aheated piece of metal cools according to the function c(x) = (.5)x ? 7, where x is measured in hours. a device is added that aids in cooling according to the function h(x) = ? x ? 2. what will be the temperature of the metal after two hours?

Find the slope of the line passing through a pair of points