Hi guys. Strange question here but i dont know how to solve and its for revision.

let A = 2x2 matrix ( 2 is the top left entry, 1 the top right entry, 7 the bottom left and 4 the bottom right)

B = 2x2 matrix (3 the top left entry, x the top right, y the bottom left and 4 the bottom right)

determine all the possible values for x and y, but such that AB = BA

please help this is a revision question for an upcoming exam so i really need to know how to do it. thanks!