A binomial has been partially factored, as shown below:

[tex]\[ x^2 - 49 = (x + 7) \][/tex]

Which of the following binomials represents the missing factor?

A. [tex]\((x + 42)\)[/tex]

B. [tex]\((x - 42)\)[/tex]

C. [tex]\((x + 7)\)[/tex]

D. [tex]\((x - 7)\)[/tex]



Answer :

To determine the missing factor, let's start by recognizing the form of the given binomial:

[tex]\[ x^2 - 49 \][/tex]

The expression [tex]\( x^2 - 49 \)[/tex] fits the pattern of a difference of squares, which is a type of algebraic expression that can be factored as follows:

[tex]\[ a^2 - b^2 = (a + b)(a - b) \][/tex]

For our given binomial [tex]\( x^2 - 49 \)[/tex], we can identify [tex]\( a \)[/tex] and [tex]\( b \)[/tex] as follows:
[tex]\[ a = x \quad \text{and} \quad b = 7 \quad \text{because} \quad 49 = 7^2 \][/tex]

Using the formula for the difference of squares, we can factor [tex]\( x^2 - 49 \)[/tex]:

[tex]\[ x^2 - 49 = (x + 7)(x - 7) \][/tex]

Given that one of the factors is [tex]\( (x + 7) \)[/tex], the missing factor must be:

[tex]\[ (x - 7) \][/tex]

To verify, we can multiply the factors together to check that they yield the original binomial:

[tex]\[ (x + 7)(x - 7) = x^2 - 7x + 7x - 49 = x^2 - 49 \][/tex]

Since this multiplication returns the original binomial [tex]\( x^2 - 49 \)[/tex], our factorization is correct.

Therefore, the missing factor is:

[tex]\[ \boxed{(x - 7)} \][/tex]