Fast math is hard for me answer the question in the picture below it wont take long

Can someone explain the elimination method to me for this problem?

Which expression is equivalent to −16y+13 ? −16(−y+13) 16(−y+2) −16(y+2) 16(−y+13)

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