Find the sum of two complex numbers and then subtract their sum from another complex number:

(- 23.4 + 7i) + (15.6 - 5i) - (19 + 11i) + (0.9i -13.3)

The given expression

(- 23.4 + 7i) + (15.6 - 5i) - (19 + 11i) + (0.9i -13.3)

Combine the real parts and then simplify it:

-23.4 +15.6 -19 - 13.3

-7.8 - 32.3 = - 40.1

Combine the imaginary parts and then simplify it:

7i - 5i - 11i + 0.9i

2i - 10.1i = - 8.1i

Combine the real part and imaginary part:

-40.1 - 8.1i

So, therefore the simplified complex number is - 40.1 - 8.1i.

Option A is correct as it accurately calculates the complex numbers

-40.1 - 8.1i

The real part of the correct result is negative (- 40.1), not positive (40.1). The imaginary part of the correct result is negative (−8.1i), not positive (8.1i.). So it is wrong

40.1 + 8.1i

The reason option C is not correct is that the imaginary part should be negative, not positive

-40.1 + 8.1i

Option D: It does not match our result because it has the wrong sign for both the real and imaginary parts

40.1 - 8.1i

Option

A

Can you summarize what you’ve understood in the above steps?