IDNLearn.com: Where your questions meet expert advice and community insights. Ask your questions and get detailed, reliable answers from our community of knowledgeable experts.

Which of the following expressions is equivalent to

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

A. [tex]\[ x^3-3x^2+2x+14 \][/tex]
B. [tex]\[ x^3+4x^2-19x+14 \][/tex]
C. [tex]\[ x^3-3x+14 \][/tex]
D. [tex]\[ x^2-2x+9 \][/tex]


Sagot :

To determine which of the provided expressions is equivalent to [tex]\((x+7)\left(x^2-3x+2\right)\)[/tex], we should expand and simplify the given expression step by step.

Given expression:
[tex]\[ (x+7)(x^2 - 3x + 2) \][/tex]

We will use the distributive property (also known as the FOIL method for binomials) to expand the expression:

1. Distribute [tex]\(x\)[/tex] from [tex]\( (x + 7) \)[/tex] to each term in [tex]\( (x^2 - 3x + 2) \)[/tex]:

[tex]\[ x \cdot x^2 + x \cdot (-3x) + x \cdot 2 = x^3 - 3x^2 + 2x \][/tex]

2. Distribute [tex]\(7\)[/tex] from [tex]\( (x + 7) \)[/tex] to each term in [tex]\( (x^2 - 3x + 2) \)[/tex]:

[tex]\[ 7 \cdot x^2 + 7 \cdot (-3x) + 7 \cdot 2 = 7x^2 - 21x + 14 \][/tex]

3. Combine the results from both distributions:

[tex]\[ (x^3 - 3x^2 + 2x) + (7x^2 - 21x + 14) \][/tex]

4. Combine like terms:

[tex]\[ x^3 + (-3x^2 + 7x^2) + (2x - 21x) + 14 \][/tex]

[tex]\[ x^3 + 4x^2 - 19x + 14 \][/tex]

Through this step-by-step expansion and simplification, we determine that the expression [tex]\((x + 7)(x^2 - 3x + 2)\)[/tex] is equivalent to:

[tex]\[ x^3 + 4x^2 - 19x + 14 \][/tex]

Therefore, the correct answer is:

[tex]\[ \boxed{B. \, x^3 + 4 x^2 - 19 x + 14} \][/tex]