Question 5325
Division of complex numbers should be discussed in your algebra textbook. Please open it to check it out.

The basic approach that you could use is: treat a problem like find {{{1/(2-i)}}}, or a reciprocal of 2-i, as finding a complex number a+bi such that (a+bi)*(2-i) = 1. That should lead you quickly to a simple system of equations, one for the real part of the product and one for complex part of the product. 

try it and come back if you have not been able to do so.