14. Which of the following polynomial functions is not written in standard form?
A. f(x) = x3 + x2 - 12x
C. y = -x4 + 16
B. f(x) = 10x3 - 3x - x5
D. y = 2x4 + 7x2 - 4x2 – 27x - 18
15. How should the polynomial function f(x) = x +2x + 3x + 5 be written in standard form?​