If 2a+ 2/a =4, what is the value of 2a^2− 2/a^2 ?

Which of the following is true for the relation f(x)=2x^2+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?

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