What is the greatest common factor of 18 and -80

How can (square root of 25) ^2 be rewritten?

If you have 12 feet of string and you cut it into equal length of 5 inches each how much string will be left

Robin spent 25% more time on his research project than he had planned he’s been an extra h ours on the project which of the following expressions could represent the number of hours rob actually spent on the project