Select the correct answer. Write (21 − 4i) − (16 + 7i) + 28i as a complex number in standard form. A. 5 + 39i B. 5 + 17i C. 5 − 39i D. 5 − 17i

Brian, chris, and damien took a math test that had 20 questions. the number of questions brian got right is 14 more than the number of questions chris got right. damien correctly answered 2 less than the number of questions chris answered correctly. if brian and damien have the same score, which statement is true?

Three cylinders have a volume of 2836 cm^3. cylinder a has a height of 900 cm. cylinder b has a height of 225 cm. cylinder c has a height of 100 cm. find the radius of each cylinder. use 3.14 as an approximate for π

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).