This is actually easier than it looks.
Just subtract the second equation from the first, and you will have the answer. Try to group like terms together while subtracting. ^ means a power.
Here is the process:
9x^3 - 5x^3 + 2x^2 - 5x - (-7x) + 4 - 4
Now, just simplify this by combining like terms. Remember that two negatives make a plus.
4x^3 + 2x^2 + 2x is the answer.
