Answer:
-v^4 +2v^3 -3v
Explanation:
Perhaps you want to collect terms. You do this by combining coefficients of like terms. Like terms are ones with the same variable expression.
(5v^4+ 8v^3) – (6v^4 + 3v + 6v^3)
= 5v^4 +8v^3 -6v^4 -3v -6v^3 . . . . . . . distribute the minus sign
= v^4(5 -6) +v^3(8 -6) +v(-3) . . . . . . . . . identify and group like terms
= -v^4 +2v^3 -3v