High School

5. Which of the following expressions is equivalent to

[tex]
\left(3x^3 + 5\right) - \left(2x^2 - 6x + 7\right) + (7x - 5) - \left(5x^2 + 3x + 3x + 2x\right)?
[/tex]

A. [tex]3x^3 - 7x^2 + 5x - 7[/tex]

B. [tex]3x^3 - 7[/tex]

C. [tex]3x^3 + 5x - 7[/tex]

D. [tex]3x^3 - 10x^2 + 9x + 7[/tex]

E. [tex]-7x^2 + 5x - 7[/tex]

Answer :

Let's simplify the given expression step-by-step:

The expression is:
[tex]\[
(3x^3 + 5) - (2x^2 - 6x + 7) + (7x - 5) - (5x^2 + 3x + 3x + 2x)
\][/tex]

Step 1: Distribute and reorder the terms

Begin by distributing the negative signs and rearranging the expression:
[tex]\[
3x^3 + 5 - 2x^2 + 6x - 7 + 7x - 5 - 5x^2 - 3x - 3x - 2x
\][/tex]

Step 2: Combine like terms

- Cubic term ([tex]\(x^3\)[/tex]):
- [tex]\(3x^3\)[/tex]

- Quadratic terms ([tex]\(x^2\)[/tex]):
- Combine [tex]\(-2x^2\)[/tex] and [tex]\(-5x^2\)[/tex]:
[tex]\[
-2x^2 - 5x^2 = -7x^2
\][/tex]

- Linear terms ([tex]\(x\)[/tex]):
- Combine [tex]\(6x + 7x - 3x - 3x - 2x\)[/tex]:
[tex]\[
6x + 7x - 3x - 3x - 2x = 5x
\][/tex]

- Constant terms:
- Combine [tex]\(5 - 7 - 5\)[/tex]:
[tex]\[
5 - 7 - 5 = -7
\][/tex]

Step 3: Write the simplified expression

The simplified expression is:
[tex]\[
3x^3 - 7x^2 + 5x - 7
\][/tex]

So, the expression that matches our simplified result is:

Option A: [tex]\(3x^3 - 7x^2 + 5x - 7\)[/tex].