Express (15-20i)/(1-2i) in a+bi form.
I'm having a lot of trouble on this problem, and I've been trying to solve it for the past couple minutes, but i've had no luck.
Thank you in advance.
Multiply numerator and denominator by the complex conjugate of 1-2i; namely by 1+2i.
Note that (1-2i)(1+2i) = 1 + 4 = 5; i.e. it no longer depends on i.
See if if you can take it from there.