The equation computed shows that the sum of the complex number is D. 13 + 12i.
From the information given, the thing that we have to do is to simply collect the like terms and solve the equation.
Therefore, the sum of (3 + 5i) + (10 + 7i) will be calculated thus:
= (3 + 5i) + (10 + 7i)
= 3 + 10 + 5i + 7i
= 13 + 12i
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