The square of a positive number increased by twice the number equals three. Find the number

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

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.

What is the value of n in the equation -1/2(2n+4)+6=-9+4(2n+1)