
Jonathan G. answered 04/30/19
Great Personal Math Teacher
Explanation:
For fractions, mathematics doesn't like radicals in the denominators, and i is a radical, even if it is imaginary. So to get it out we would multiply by it on the top and the bottom of the fraction, however this time it's a little more complicated. Since the denominator is 6+i it is a complex number (a combination of a real and imaginary number), so we have to multiply by what's called the complex conjugate. The complex conjugate is the exact same numbers, but with a different sign on the imaginary number. In this case 6-i.
Solution:
3/(6+i), we need to multiply 6-i to the top and bottom of the fraction, then reduce where possible.
3*(6-i)=18-3i
(6+i)(6-i)= 36+6i-6i-i2= 36-i2= 36-(-1)= 37
So the result is (18-3i)/37, that can't reduce anywhere because 37 is prime, so final answer
18/37 - 3i/37