Answer
10x$^3$-9x$^2$+2x+11
Work Step by Step
Distribute the negative sign to the parentheses and then combine like terms vertically.
$\qquad5x^3-6x^2-9x+14$
$\underline{-(-5x^3+3x^2-11x+3)}$
$\qquad$$\qquad$$\quad$$\downarrow$
$\quad5x^3-6x^2-9x+14$
$\underline{+\,5x^3-3x^2+11x-3)}$
$\quad10x^3-9x^2+2x+11$