Can some one please explain how do solve this please and thank you

What is the measure of ac? 5 units 13 units 26 units 39 units 3x- 2b 6x + 9

Two variables, x and y, vary inversely, and x=12 when y=4. what is the value of y when x=3?

Abag contains 3 red marbles, 2 blue marbles, and 2 green marbles. one marble is picked, then another marble. assume that the selections are made with replacement. a) find the probability of picking two red marbles with replacement. b) find the probability of picking a red marble and a blue marble. assume the selections are made without replacement. c) find the probability of picking two red marbles without replacement. d) find the probability of picking a red marble and a blue marble without replacement.