Calculate the subtraction (8.5 - 1.8i) - (-1.3 + 2.7i). Provide the answer in the form of a + bi.
To subtract complex numbers, we subtract the real parts and the imaginary parts separately.
The real part of (8.5 - 1.8i) is 8.5, and the real part of (-1.3 + 2.7i) is -1.3. So, their difference in the real part is:
8.5 - (-1.3) = 8.5 + 1.3 = 9.8
The imaginary part of (8.5 - 1.8i) is -1.8i, and the imaginary part of (-1.3 + 2.7i) is 2.7i. So, their difference in the imaginary part is:
-1.8i - 2.7i = -4.5i
Therefore, the subtraction of (8.5 - 1.8i) - (-1.3 + 2.7i) is:
9.8 - 4.5i
Hence, the answer is 9.8 - 4.5i.