What is the missing polynomial?

[tex]\[ -\left(20-4x-5x^2\right) = 20 - 7x^2 \][/tex]

A. [tex]\( 4x - 12x^2 \)[/tex]

B. [tex]\( 4x - 2x^2 \)[/tex]

C. [tex]\( 40 - 4x - 12x^2 \)[/tex]

D. [tex]\( 40 - 4x - 2x^2 \)[/tex]



Answer :

To solve for the missing polynomial, let's start by analyzing the given expression and the target expression:

1. We have the equation:
[tex]\[ -\left(20 - 4x - 5x^2 \right) = 20 - 7x^2. \][/tex]

2. First, distribute the negative sign through the left expression inside the parentheses:
[tex]\[ -20 + 4x + 5x^2. \][/tex]

3. Simplify the left expression:
[tex]\[ 5x^2 + 4x - 20. \][/tex]

Now we need to find which of the given options, when simplified, equals [tex]\( 5x^2 + 4x - 20 \)[/tex]:

- Option 1: [tex]\( 4x - 12x^2 \)[/tex]:
This does not match [tex]\( 5x^2 + 4x - 20 \)[/tex].

- Option 2: [tex]\( 4x - 2x^2 \)[/tex]:
This does not match [tex]\( 5x^2 + 4x - 20 \)[/tex].

- Option 3: [tex]\( 40 - 4x - 12x^2 \)[/tex]:
Simplify and compare:
[tex]\[ 40 - 4x - 12x^2 \neq 5x^2 + 4x - 20. \][/tex]

- Option 4: [tex]\( 40 - 4x - 2x^2 \)[/tex]:
Simplify and compare:
[tex]\[ 40 - 4x - 2x^2 \neq 5x^2 + 4x - 20. \][/tex]

4. None of the given expressions simplify to [tex]\(5x^2 + 4x - 20\)[/tex].

Therefore, the correct answer is:
[tex]\[ \boxed{\text{None of the given options are correct}} \][/tex]