what is the sum of 12 - 5i and -3 + 4i?\n-16 + 63i\n9 - i\n9 - 9i\n15 - 9i

Explanation:

Step1: Add real - parts

Add the real parts of the two complex numbers: $(12)+(-3)=12 - 3=9$.

Step2: Add imaginary - parts

Add the imaginary parts of the two complex numbers: $(-5i)+(4i)=(-5 + 4)i=-i$.

Step3: Combine results

Combine the results of the real - part addition and the imaginary - part addition. The sum is $9 - i$.

Answer:

B. $9 - i$