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Consider the expressions given below:
A. \(2x^3 - x^2 - 6x\)
B. \(2x^3 + 8x + 4\)
C. \(3x^4 + x^2 + x - 7\)
D. \(3x^4 - 3x^2 + 5x - 7\)

For each expression below, select the letter that corresponds to the equivalent expression from the given list.

1. \((4x^3 - 4 + 7x) - (2x^3 - x - 8)\) is equivalent to expression \(\square\).

2. \((-3x^2 + x^4 + x) + (2x^4 - 7 + 4x)\) is equivalent to expression \(\square\).

3. [tex]\((x^2 - 2x)(2x + 3)\)[/tex] is equivalent to expression [tex]\(\square\)[/tex].


Sagot :

Let's work through each expression one step at a time to determine which of the given options (A, B, C, or D) matches the given expressions.

### First Expression: \((4x^3 - 4 + 7x) - (2x^3 - x - 8)\)

1. Distribute the negative sign in the second group:
[tex]\[ (4x^3 - 4 + 7x) - 2x^3 + x + 8 \][/tex]

2. Combine like terms:
[tex]\[ 4x^3 - 2x^3 + 7x + x - 4 + 8 = 2x^3 + 8x + 4 \][/tex]

This matches expression B, which is:
[tex]\[ B. \, 2x^3 + 8x + 4 \][/tex]

So, \((4x^3 - 4 + 7x) - (2x^3 - x - 8)\) is equivalent to expression B.

### Second Expression: \((-3x^2 + x^4 + x) + (2x^4 - 7 + 4x)\)

1. Combine like terms directly:
[tex]\[ x^4 + 2x^4 - 3x^2 + x + 4x - 7 = 3x^4 + x - 3x^2 - 7 \][/tex]

This matches expression D, which is:
[tex]\[ D. \, 3x^4 - 3x^2 + 5x - 7 \][/tex]

So, \((-3x^2 + x^4 + x) + (2x^4 - 7 + 4x)\) is equivalent to expression D.

### Third Expression: \((x^2 - 2x)(2x + 3)\)

1. Distribute the terms:
[tex]\[ x^2 \cdot 2x + x^2 \cdot 3 - 2x \cdot 2x - 2x \cdot 3 = 2x^3 + 3x^2 - 4x^2 - 6x = 2x^3 - x^2 - 6x \][/tex]

This matches expression A, which is:
[tex]\[ A. \, 2x^3 - x^2 - 6x \][/tex]

So, \((x^2 - 2x) (2x + 3)\) is equivalent to expression A.

### Summary
[tex]\[ \begin{array}{c} \left(4x^3 - 4 + 7x\right) - \left(2x^3 - x - 8\right) \text{ is equivalent to expression } B \\ \left(-3x^2 + x^4 + x\right) + \left(2x^4 - 7 + 4x\right) \text{ is equivalent to expression } D \\ \left(x^2 - 2x\right) (2x + 3) \text{ is equivalent to expression } A \\ \end{array} \][/tex]

So the final answers are:
- \((4x^3 - 4 + 7x) - (2x^3 - x - 8)\) is equivalent to expression B.
- \((-3x^2 + x^4 + x) + (2x^4 - 7 + 4x)\) is equivalent to expression D.
- [tex]\((x^2 - 2x) (2x + 3)\)[/tex] is equivalent to expression A.