College

3. What is [tex]$x^4 - 2x^3 + 7x^5$[/tex] subtracted from [tex]$x^3 - 6x^5 + 7x^4$[/tex]?

A. [tex][tex]$13x^5 - 6x^4 - 3x^3$[/tex][/tex]
B. [tex]$x^5 + 6x^4 - x^3$[/tex]
C. [tex]$x^5 + 8x^4 - x^3$[/tex]
D. [tex][tex]$-13x^5 + 6x^4 + 3x^3$[/tex][/tex]

Answer :

We start with the problem of finding the difference between the two expressions:

[tex]$$
\text{Expression 1: } x^3 - 6x^5 + 7x^4
$$[/tex]

[tex]$$
\text{Expression 2: } x^4 - 2x^3 + 7x^5
$$[/tex]

Since we need to subtract Expression 2 from Expression 1, we write:

[tex]$$
(x^3 - 6x^5 + 7x^4) - (x^4 - 2x^3 + 7x^5)
$$[/tex]

### Step 1: Distribute the Negative Sign

We distribute the negative sign to each term inside the second parenthesis:

[tex]$$
x^3 - 6x^5 + 7x^4 - x^4 + 2x^3 - 7x^5
$$[/tex]

### Step 2: Combine Like Terms

- For the [tex]\(x^5\)[/tex] terms:

[tex]\[
-6x^5 - 7x^5 = -13x^5
\][/tex]

- For the [tex]\(x^4\)[/tex] terms:

[tex]\[
7x^4 - x^4 = 6x^4
\][/tex]

- For the [tex]\(x^3\)[/tex] terms:

[tex]\[
x^3 + 2x^3 = 3x^3
\][/tex]

### Step 3: Write the Final Expression

Combining the results:

[tex]$$
-13x^5 + 6x^4 + 3x^3
$$[/tex]

Thus, the final answer is:

[tex]$$
\boxed{-13x^5 + 6x^4 + 3x^3}
$$[/tex]

This matches answer option D.