How is this done, i try but i dont understand it

Plz answer asap plz which is a solution to the equation 4b2 − 11b = 28 + 5b2? a) −5 b) −4 c) −3 d) 4

Abag contains 4 red, 7 blue and 5 yellow marbles. event a is defined as drawing a yellow marble on the first draw and event b is defined as drawing a blue marble on the second draw. if two marbles are drawn from the bag, one after the other and not replaced, what is p(b|a) expressed in simplest form? a. 7/16 b. 7/15 c. 14/16 d. 14/15

Can you me find the missing length. i attached an image.