To subtract the given expression, we need to combine like terms.
First, let's distribute the negative sign to every term inside the parentheses of the second expression to make it negative:
(4x^3 + 5x^2 - 2x - 1) - (3x^2 + 7x - 4)
= 4x^3 + 5x^2 - 2x - 1 - 3x^2 - 7x + 4
Next, we can combine the similar terms. Start by combining the x^3 terms:
4x^3 - 3x^2
= x^3
Next, we combine the x^2 terms:
5x^2 - 3x^2
= 2x^2
Now, let's combine the x terms:
-2x - 7x
= -9x
Finally, combine the constant terms:
-1 + 4
= 3
Putting it all together, the simplified expression is:
x^3 + 2x^2 - 9x + 3