Which of the following isn’t a solution to cos 2x + cos x=0 on the interval [0,2pi)

Zroms according to the synthetic division below, which of the following statements are true? check all that apply. 352 -2 6 -12 12 2 4 0 i a. (x-3) is a factor of 2x2 - 2x - 12. b. the number 3 is a root of f(x) = 2x2 - 2x - 12. c. (2x2 - 2x - 12) = (x + 3) = (2x + 4) d. (2x2 - 2x-12) - (x-3) = (2x + 4) e. (x+3) is a factor of 2x2 - 2x - 12. o f. the number -3 is a root of fx) = 2x2 - 2x - 12. previous