In the addition of two binomials you have to add separately each monomial as follows:
(3 + 2x) + (4 – 5x) =
= (3 + 4) + (2x - 5x) =
= 7 - 3x
Analogously, the sum of the complex numbers 3 + 2i and 4 – 5i is made adding the two real parts from one side, and the two imaginary parts from the other side, as follows:
We have the binomials 3 + 2x and 4 - 5x. When we sum binomials, we have to sum the independent terms with each other and the first degree terms with each other. Then:
(3 + 2x) + (4 - 5x) = (3 + 4) + (2-5)x = 7 - 3x
Therefore, we can cosider i as a variable and the sum of the complex number would be:
