What is the missing polynomial? ? - (20 - 4x - 5x^2) = 20 - 7x^2

1. Identify the equation: The problem asks to find the missing polynomial in the equation: $? - (20 - 4x - 5x^2) = 20 - 7x^2$.
2. Isolate the missing polynomial: To find the missing polynomial, we need to isolate it. We can do this by adding $(20 - 4x - 5x^2)$ to both sides of the equation.
$$? = (20 - 7x^2) + (20 - 4x - 5x^2)$$
3. Combine like terms: Now, we combine the like terms on the right side of the equation.
Combine the constant terms: $20 + 20 = 40$.
Combine the $x$ terms: There is only one $x$ term, which is $-4x$.
Combine the $x^2$ terms: $-7x^2 - 5x^2 = -12x^2$.
4. Write the resulting polynomial: Putting the combined terms together, we get the missing polynomial.
$$? = 40 - 4x - 12x^2$$