C. 8- 6i
(3- i) to the power of 2 (expand the expression)
9- 6 i + i to the power of 2
calculate
9 - 6i - 1
calculate
8- 6i.
So this is a special triangle. The 30-60-90 triangle rule states that if the short leg is y, then the hypotenuse is 2y and the long leg is y√3.
In this case, the short leg is 5√3 since that times √3 makes 15.
Now with the hypotenuse, just multiply 5√3 with 2, and your answer should be 10√3, or C.
X^2+4+10=0
x=(-4(+/-)root16-40)/2, so we now know that the zeros are imaginary, because you can't square root a negative number and 16-40 is -24
so the two roots are…
-2+iroot6 and -2-iroot6
Your answer is 7.
I subtracted 5 from 12 to find the missing number for KL that is 7.
Therefore, your answer is 7