Argghhh no ones answering my questions. could someone answer theses questions

Which representation has a constant of variation of -2.5

Create a graph for the demand for starfish using the following data table: quantity/price of starfish quantity (x axis) of starfish in dozens price (y axis) of starfish per dozen 0 8 2 6 3 5 5 2 7 1 9 0 is the relationship between the price of starfish and the quantity demanded inverse or direct? why? how many dozens of starfish are demanded at a price of five? calculate the slope of the line between the prices of 6 (quantity of 2) and 1 (quantity of 7) per dozen. describe the line when there is a direct relationship between price and quantity.

Olga bought a new skirt that cost $20. sales tax is 5%. how much did olga pay, including sales tax? 7.