Answer:
The values of a,b,c and d are as follows:
a = 3, b = -12, c = -5, d = 10
Explanation:
Given functions are:

We have to find the value of f(x) - g(x). This means we have to subtract function g(x) from function f(x)
So,

Combining alike terms

Now it was given that:
f(x)- g(x)= ax^3+bx^2+ cx+d
By comparing both we get
a = 3, b = -12, c = -5, d = 10
Hence,
The values of a,b,c and d are as follows:
a = 3, b = -12, c = -5, d = 10