Add the complex numbers 5 - 2i and 3 + 7i. What is the sum?

1. Adding complex numbers combines the real parts and combines the imaginary parts separately. 2. The real parts give 5 plus 3, which is 8. 3. The imaginary parts give negative 2 plus 7, which is 5. 4. So the sum is 8 + 5i, and subtracting instead would have given 2 - 9i. _Source: OpenStax Precalculus (CC BY 4.0), section 3.1 Complex Numbers_