X^2 = 4 x (20-4) =64. So x =8
We are asked to write the following fraction of complex numbers in standard form:

.
Whenever we are dividing by a complex number by another complex number a+bi, to write the result in standard form, we multiply the expressions in the numerator and denominator by the conjugate of a+bi, that is a-bi:

in the numerator we distribute (3-i) to 1 and -5i, in the denominator we use the difference of squares formula

, and

:


Answer: D
The more people there are, the longer the wait. if there is one person in line the wait would be 20 min divided 160=1/8 min 220 people is 1/8 min x 220= 27.5 min.
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The difference is 6 because it is what we get when we subtract 8 and 2.
Final answer: 6