Commutative property of addition is
a+b = b+a, that is if we change the positions of the numbers, the result is same. For e.g. 2 + 3 = 3+2 .
In the given question , which is (-1+i) + (21+5i), we can use commutative property of addition to simplify it to the simpler form .
And the first step is to combine the like terms that is
(-1+21)+(i+5i). And tht's the required answer or that's the first step which is the commutative property of addition .
