Hey guess what size i ware

How do you work out 21.3-8= show your working. plz

Use the rule of 72 to calculate how long it will take for your money to double if its earning 6% in interest. a. 12yrs b. 16yrs c. 36yrs d. 72yrs

Which source would provide the most bias-free information about smoking and increased health risks? a) a website created by heart disease patients b) a research study conducted by the mayo clinic eliminate c) a public service message sponsored by tobacco companies d) an online question forum conducted by attorneys for cardiac specialists