Considering the definition and sum of complex numbers, the sum (9 + 4i) + (–1 - 7i) gives as a result 8 -3i.
Complex numbers are combinations of real numbers and imaginary numbers.
In other words, complex numbers are numbers that have a real part and an imaginary part.
The most common representation of a complex number is the sum of a real part and an imaginary part. At the same time, the imaginary part is divided between the imaginary part and the imaginary unit:
z = a + bi
where
This expression is called the binomial form of the complex number z.
To add two or more complex numbers, you simply have to add the real and imaginary parts separately. That is, being z1 = a + bi and z2 = c + di, the sum of both complex numbers is calculated as:
z1 + z2 = (a + c) + (b + d) i
In this case, to obtain 8 -3i you have to sum:
(9 + 4i) + (–1 – 7i)= (9-1) + (4-7)i= 8 - 3i
So, the sum (9 + 4i) + (–1 - 7i) gives as a result 8 -3i.
Learn more about complex number:
