If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
Current time:0:00Total duration:1:11

Video transcript

we're asked to add the complex number 5 plus 2i to the other complex number 3 minus 7i and as we'll see when we're adding complex numbers you can only add the real parts to each other and you can only add the imaginary parts to each other so let's add the real parts so we have a 5 plus a 3 so we have a 5 plus a 3 and then the imaginary parts we have a 2 I so plus 2i and then we have a negative 7i or we're adding or we're subtracting 7 I so minus 7i right over here and 5 plus 3 that's pretty straightforward that's just going to be 8 and then if I have 2 of something and from that I subtract 7 of that something and in this case the something is the imaginary unit the number I if I have 2 of if I have 2 eyes and I take away 7 eyes then I have negative 5 is 2 minus 7 is negative 5 so then I have negative 5i so when you add these two complex numbers you get 8 minus 5i you get another complex number has a real part and an imaginary part