Question

It performs the following operations of the complex numbers would greatly appreciate friends...:)

Answer 1

Add the real numbers together.
Also perform operation on the imaginary ones as well.

(5i +4) +(4i -3)  = 5i + 4i + 4- 3 =  9i +1.
(2+i) - (3+4i)    = 2 +i -3 -4i  = 2-3 + i - 4i = -1 -3i.

Cheers.

Answer 2

(5i+4) + (4i-3)
5i+4i-3+4
9i - 1

(2+i) - (3+4i)
(2+i) + (-3 - 4i)
-1 -3i

Each part, real numbers and imaginary, are to be taken as separate pieces; add them with and subtract them by each other as you normally would. :)