Sava D. answered 07/16/19
Math master degree tutor with good understanding of precalculus
(5 - i)/(6 + 5i)
= [(5 - i)(6 - 5i)] / [(6 + 5i)(6 - 5i)]
=[30 + 5i2 - 6i - 25i] / [36 - 25i2]
=[30 - 5 -31i] / [36 + 25]
=[25 -31i] / 61
=25/61 - 31/61i
Explanation: We use the complex conjugate of (6 + 5i) to make the denominator real number. Then, we simplify the numerator and the denominator. We use the fact that i2 = -1 and simplify.