#### Answer

(1) $-(x^4-8x^3+6x)$
(2) $-x^4+8x^3-6x$

#### Work Step by Step

Two expressions equivalent to the opposite of a polynomial can be found by:
(1) taking the negative of the polynomial; and
(2) changing the sign of each term of the polynomial
Thus, two expressions equivalent to the opposite of the given polynomial are:
(1) $-(x^4-8x^3+6x)$
(2) $-x^4+8x^3-6x$