Square roots of numbers that are not perfect squares are

Which describes the difference between the graph of f(x)=x^2 and g(x)=-(x^2-2)

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?

Tatiana reads 40 pages of her book every night for x number of nights. write an expression that shows the number of pages she has read