I don’t understand nothing

What is the solution of log2  (3x  -  7)  =  3? 4 5

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?

Select the lengths in centimeters that would form a right triangle