Im Having A Brindis For My Wedding.. Im Having A Problem With This Seemingly Easy Physics Vector Question?

Im having a problem with this seemingly easy physics vector question? - im having a brindis for my wedding..

A vehicle that has a size of 29 units and points in the positive direction. where is the vector B to A, the resultant vector of a B + in the negative direction and a size of 14 units. Find the magnitude and direction of B. Need U To the Pythagorean Theorem for this application, because I always get the wrong answer.
the correct answer, while the return is the text of 43 units and in the negative sense. IM is not received, then I would someone to tell me exactly how this problem is derived from the like.