I need help right aways plz help

Clara solved the equation 7/3x = −2/3 as shown → 7/3x( 3/7 ) = −2/3 ( 3/7 ) x = −14 what is clara’s error?

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?

Could somebody me with this radical simplification?