K(x)=½ x-10 find k(20)

Rewrite the following without an exponent. (5/8)-1

Which expression is equivalent to 2x^2+7x+4?

The number if marbles of different colors stored in a hat is listed below: 4 red marbles 10 green marbles 7 blue marbles. without looking in the hat, dan takes out a marble at random. he replaces the marble and then takes out another marble from the hat. what is the probability that dan takes out a blue marble in both draws?