Which term completes the product so that it is the difference of squares?

[tex]\[ (-5x - 3)(-5x + \_\_\_\_) \][/tex]

A. \(-9\)

B. \(-3\)

C. \(3\)

D. [tex]\(9\)[/tex]



Answer :

To find the term that completes the product \((-5x - 3)(-5x + \_\_\_\_\_) \) so that it becomes a difference of squares, let's consider the nature of difference of squares.

The difference of squares formula is given by:
[tex]\[ a^2 - b^2 = (a - b)(a + b) \][/tex]

Here, we want our expression to take the form of \( (-5x - 3)(-5x + \text{some term}) \). For it to be a difference of squares, the second binomial should be in the form \( (-5x + b) \), and our end product should look like:
[tex]\[ (-5x)^2 - (\text{some term})^2 \][/tex]

Now let's break down the terms.

1. \( \text{First term squared} \):
[tex]\[ (-5x) \times (-5x) = 25x^2 \][/tex]
Thus, the first term squared is 25x^2.

2. \( \text{Second term squared} \):
We know from analyzing the numbers and the result given:
[tex]\[ \text{Second term's contribution is } -9 \][/tex]
So, we need to figure out what squared term will give the numeric result that matches.
To find our value \( b \):
[tex]\[ b^2 = \left(3\right)^2 = 9 \][/tex]

Since we are ensuring the second term completes a difference of squares, the numerical part added to the product should be appropriately balanced such that it resembles the \((-5 x - 3)\) counterpart forming.

Now, combining all findings, the term \( b \) can be:

[tex]\[ b = \pm 3 \text{ or } \pm 9 \][/tex]

We validate this as:

[tex]\[ (-5 x - 3)( - 5 x + [3 \text{ or } -3] \text{ or } [9 \text{ or } -9]) \][/tex]

From the choices, only one number will fit properly into the product ensuring \( b \):
[tex]\[ a^2 - b^2 = 25x^2 - 9 \][/tex]

Finally, this elaboration shows:

[tex]\[ \boxed{9} \][/tex]

is the term that completes the product so it is the difference of squares.

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