Which of the following sets is closed under subtraction?
integers
whole numbers
natural numbers
irrational numbers

What does x = in this equation x+3+2x=x+5

The figures below are made out of circles, semicircles, quarter circles, and a square. find the area and the perimeter of each figure and give your answers as a completely simplified exact value in terms of π (no approximations).

For what value of (y) is 3^3/3^y =1/9