Which point on the unit circle corresponds to -pi?

What is the result of adding the system of equations? 2x+y=4 3x-y=6

Use composition to determine if (x) or h(x) is the inverse of f(x) for the limited domain x2-1.

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?