What addition problem with two complex number would give me a sum of 12 + 8i

Which is the equation of an ellipse with directrices at x = ±4 and foci at (2, 0) and (−2, 0)?

True or false? a circle could be circumscribed about the quadrilateral below.

Atextile fiber manufacturer is investigating a new drapery yarn, which the company claims has a mean thread elongation of 12 kilograms with a standard deviation of 0.5 kilograms. the company wishes to test the hypothesis upper h subscript 0 baseline colon mu equals 12 against upper h subscript 1 baseline colon mu less-than 12 using a random sample of n equals 4 specimens. calculate the p-value if the observed statistic is x overbar equals 11.8. round your final answer to five decimal places (e.g. 98.76543).