Can you please help explain this equation to me? Please and thank you!

f ics lab, 0.500-kg cart (Cart A) moving rightward with a speed of 92.8 cm/s collides with a 1.50-kg cart (Cart 3. In a phys ve as a single object after the B) moving leftward with a speed of 21.6 cm/s. The two carts stick together and mo collision. Determine the postcollision speed of the two carts. l Answer (in full sentence): l m