Rich G. answered 07/16/19
Experienced Pre-Calculus/Trigonometry Tutor
In order to solve a problem like this we have to multiply top and bottom by the conjugate of the denominator - or in simple terms, you multiply by the opposite of the bottom number.
So in your problem, we have
6-3i/1-6i
The conjugate of the denominator is 1+6i, so when we multiply top and bottom by 1+6i, the imaginary terms in the bottom will cancel out and no longer be an issue in the denominator
6-3i/1-6i * 1+6i/1+6i = (6-3i)(1+6i)/(1-6i)(1+6i)
Now we can multiply by using FOIL (first, outer, inner, last)
(6-3i)(1+6i)/(1-6i)(1+6i) = (6- 3i + 36i -18i^2)/(1 - 6i + 6i -36i^2) = (6+33i - 18i^2) / (1 - 36i^2)
Since i = √-1, i2 = -1. Now we can substitute -1 for i2 in the above equation to get
(6+33i - 18i^2) / (1 - 36i^2) = (6+33i - 18(-1)) / (1 - 36(-1))
(24+ 33i)/37
It's customary to split up a number like this and write it as two fractions:
24/37 + 33i/37