1. ## Complex number

Given that
Z1=(13-9i)/(-8+3i) and
Z2=(-8-7i)/(-11+8i)

What is z1 + z2 in the form x + yi ?

I tried and got 18341/23690 +24153i/23690 which is not correct
?
Thanks

2. Originally Posted by taurus
Given that
Z1=(13-9i)/(-8+3i) and
Z2=(-8-7i)/(-11+8i)

What is z1 + z2 in the form x + yi ?

I tried and got 18341/23690 +24153i/23690 which is not correct
?
Thanks
What I would recommend doing is the following: multiple each term by the conjugate of their denominators as follows

$\displaystyle z_1=\frac{13-9i}{-8+3i}\cdot\frac{-8-3i}{-8-3i}=-\frac{131}{73}+\frac{33i}{73}$
$\displaystyle z_2=\frac{-8-7i}{-11+8i}\cdot\frac{-11-8i}{-11-8i}=-\frac{32}{185}+\frac{141i}{185}$
(verify)

Maybe now you can get $\displaystyle z_1+z_2$ into $\displaystyle x+yi$ form. I get $\displaystyle z_1+z_2=-\frac{26571}{13505}+\frac{16398}{13505}i$

Hoped this helped you out!!

3. that doesnt seem correct either when i enter it in computer

4. Originally Posted by Chris L T521
$\displaystyle z_2=\frac{-8-7i}{-11+8i}\cdot\frac{-11-8i}{-11-8i}=-\frac{32}{185}+\frac{141i}{185}$
I caught the error right here...it should be $\displaystyle \frac{32}{185}+\frac{141i}{185}$, not $\displaystyle -\frac{32}{185}+\frac{141i}{185}$. Thus my answer should turn out to be $\displaystyle z_1+z_2=-\frac{21899}{13505}+\frac{16938}{13505}i$. This should be the correct answer now. Sorry about that!

5. hmmmm