PLS HELP WILL MARK BRAINLIEST, NO FAKE ANSWERS OR WILL BE REPORTED.

Answer:
TRUE
Step-by-step explanation:
Finding the opposite is the same as multiplying everything by -1
ax^4 × -1 = -ax^4
-bx³ × -1 = bx³
-cx × -1 = cx
d × -1 = -d
-ax^4 + bx³ + cx - d