1/5^9=5^? This is a mathy math question please help.

Ifurniture stores having a weekend sale and is offering 20% discount on patio chairs and table the sales tax on furniture is 6.25 using function composition how can you represent the total amount a that you would need to pay for this furniture that cost x dollars

Me n o w. i need t h i s. 10 points

The base of the rectangle pyramid is 13 inches long and 12 inches wide the height of the pyramid is 18 inches . what is the volume of the pyramid ?