Pls help I sad Without using a calculator, find all the roots of the equation below.
x^4 - 2x^3 + 6x^2 - 18x - 27 = 0
(Use a comma to separate answers as needed. Express complex numbers in terms of i)
The root(s) is(are)

A. find the power of the test, when the null hypothesis assumes a population mean of mu = 450, with a population standard deviation of 156, the sample size is 5 and the true mean is 638.47 with confidence intervals of 95 b. find the power of the test, when the null hypothesis assumes a population mean of mu = 644, with a population standard deviation of 174, the sample size is 3 and the true mean is 744.04 with confidence intervals of 95% c. find the power of the test, when the null hypothesis assumes a population mean of mu = 510, with a population standard deviation of 126, the sample size is 10 and the true mean is 529.44 with confidence intervals of 95