College

Perform the operation:

[tex]
\[
\left(-9x^5 + 2x^7 - 2 - 4x^6\right) - \left(-6 - 9x^6 + 7x^7 - 2x^5\right)
\]
[/tex]

A. [tex]\(9x^7 - 13x^6 - 11x^5 + 4\)[/tex]

B. [tex]\(-5x^7 + 5x^6 - 7x^5 + 4\)[/tex]

C. [tex]\(9x^7 - 13x^6 - 11x^5 - 8\)[/tex]

D. [tex]\(-5x^7 - 13x^6 - 11x^5 - 8\)[/tex]

Answer :

Sure, let's solve the problem step-by-step:

We need to perform the operation:

[tex]\[
(-9x^5 + 2x^7 - 2 - 4x^6) - (-6 - 9x^6 + 7x^7 - 2x^5)
\][/tex]

### Step 1: Distribute the negative sign

Subtracting a polynomial is the same as adding the opposite of each term inside it. Thus, we change the signs of each term in the second polynomial:

[tex]\[
- (-6 - 9x^6 + 7x^7 - 2x^5) = 6 + 9x^6 - 7x^7 + 2x^5
\][/tex]

### Step 2: Write the expression with distributed signs

Now, rewrite the expression with the distributed signs:
[tex]\[
(-9x^5 + 2x^7 - 2 - 4x^6) + (6 + 9x^6 - 7x^7 + 2x^5)
\][/tex]

### Step 3: Combine like terms

Next, we combine like terms:

- Combine the [tex]\(x^7\)[/tex] terms: [tex]\(2x^7 - 7x^7 = -5x^7\)[/tex]
- Combine the [tex]\(x^6\)[/tex] terms: [tex]\(-4x^6 + 9x^6 = 5x^6\)[/tex]
- Combine the [tex]\(x^5\)[/tex] terms: [tex]\(-9x^5 + 2x^5 = -7x^5\)[/tex]
- Combine the constant terms: [tex]\(-2 + 6 = 4\)[/tex]

### Final Expression

Putting it all together, we get:

[tex]\[
-5x^7 + 5x^6 - 7x^5 + 4
\][/tex]

So, the correct choice from the given options is:

[tex]\[
-5x^7 + 5x^6 - 7x^5 + 4
\][/tex]