SOLUTION: Hello! I really need some help with how to do this. I can't figure it out with the i. 4-3i/7+3i (four minus three i, divided by seven plus three i) Thank you!! Melissa

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson  -> Lesson -> SOLUTION: Hello! I really need some help with how to do this. I can't figure it out with the i. 4-3i/7+3i (four minus three i, divided by seven plus three i) Thank you!! Melissa      Log On


   

Question 701723: Hello!
I really need some help with how to do this. I can't figure it out with the i.
4-3i/7+3i
(four minus three i, divided by seven plus three i)
Thank you!!
Melissa
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
%28%284-3i%29%29%2F%28%287%2B3i%29%29
multiply by the conjugate of the denominator over itself
%28%284-3i%29%29%2F%28%287%2B3i%29%29 * %28%287-3i%29%29%2F%28%287-3i%29%29 = %28%2828-12i-21i%2B9%28i%5E2%29%29%29%2F%28%2849-21i%2B21i-9%28i%5E2%29%29%29 =
Notice that when you FOIL the denominators, the middle term containing "i" drops out, and i^2 = -1
%28%2828-33i%2B9%28-1%29%29%29%2F%28%2849-9%28-1%29%29%29 = %28%2828-33i-9%29%29%2F%28%2849%2B9%29%29 = %28%2819-33i%29%29%2F%28%2858%29%29