What is the degree of a polynomial that has roots of -2, 4i and -4i ?

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.

The value of cos 30° is the same as which of the following?

36x2 + 49y2 = 1,764 the foci are located at: (-√13, 0) and (√13,0) (0, -√13) and (0,√13) (-1, 0) and (1, 0)edit: the answer is (- the square root of 13, 0) and (the square root of 13, 0)