(i need this answered super fast im on a deadline ! ) which ratios can form a proportion? 9/45, 8/40 8/12, 12/21 8/12, 12/15 9/22, 14/28

Which ratio is equivalent to 10: 85

Really need on these. i have no idea what to do

Steve wants to develop a way to find the total cost of any item including sales tax. the sales tax in his city is 6%. his friend jenna writes the expression x + 6x where x is the cost of the item. explain whether her expression is correct based on the situation.