Refer to figure.
Induced drag varies inversely with the square of the airspeed and decreases when airspeed increases. Induced drag is caused when an object redirects the airflow. A wing produces lift by creating a pressure difference. This pressure difference is caused by the shape of the airfoil, causing the airflow on top to accelerate, creating a low pressure on top of the wing and high pressure below the wing. This pressure difference naturally wants to restore towards a uniform pressure, which creates vortices around the wingtip.

Parasite drag is caused if an airfoil is moving through the air. It is the result of form drag and skin friction drag and increases as the square of the airspeed.

Total drag is the resulting factor if you add induced drag and parasite drag together.

From the curve of the drag vs airspeed, we conclude that Total drag has a minimum value at a certain speed and increases at higher as well as lower speeds. At this certain speed, where Total drag is minimum, Induced drag is equal to Parasite drag.