10 EQ and Pan EQ stands for equalisation and is concerned with shaping the tone of the instruments on a channel.
A basic mixer will allow you to cut or boost the bass and treble but more expensive models will also have one or two 'swept mids'.
A swept mid is a tone control of two halves. There's a cut/boost knob and a frequency control.
That allows you to home in on an exact frequency and bring it out or back it off.
Mid-range is an important part of the sound of an instrument because it's where your hearing is most sensitive and fine control over mid-range can be vital in getting a good mix together.
The pan knob allows you to move the sound of a signal from left to right in a stereo mix.
It can be useful to separate out similar instruments and will help create a full sound-stage in your final mix.