SOLUTION: my homework problem asks: perform the indicated operations. give result in standard form. the preoblem is: 9+5i / 3-4i. I multiplied numerator and denominatorby the conjegate (3+

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: my homework problem asks: perform the indicated operations. give result in standard form. the preoblem is: 9+5i / 3-4i. I multiplied numerator and denominatorby the conjegate (3+      Log On


   

Question 20512: my homework problem asks: perform the indicated operations. give result in standard form. the preoblem is: 9+5i / 3-4i. I multiplied numerator and denominatorby the conjegate (3+4i) and my final answer is 7/25 + 51/25 i. Is this the correct answer?
My other problem is : multiply: cubed root of 25xy times cubed root of 9xy. my answer is cubed root of 225x2y2. Did i do this right? do i need to reduce further or am i way off? I would appreciate any help you could give me. Thank you in advance for all your help. -Clyde
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
1) You did it correctly by multiplying the numerator and denominator by the conjegate(sic) (spelled...conjugate).
%289%2B5i%29%2F%283-4i%29 Multiply by %283%2B4i%29%2F%283%2B4i%29
%289%2B5i%29%283%2B4i%29%2F%283-4i%29%283%2B4i%29 = %2827%2B36i%2B15i%2B20i%5E2%29%2F%289-16i%5E2%29 Simplify, remembering that i^2 = -1
%2827-20%2B51i%29%2F%289%2B16%29 Simplify and write in standard form: %28a+%2B+bi%29
%287%2B51i%29%2F25 = %287%2F25%29+%2B+%2851%2F25%29i
2) You have also done this one correctly.
= %28225x%5E2y%5E2%29%5E%281%2F3%29
N.B. x^(1/3) = cube root(x)