Select the correct answer.

Factor the expression, [tex]$40x^2 - 10$[/tex].

A. [tex]$(7x + 4)(7x - 4)$[/tex]
B. [tex][tex]$(4x - 7)(4x - 7)$[/tex][/tex]
C. [tex]$(4x + 7)(4x - 7)$[/tex]
D. [tex]$(7x - 4)(7x - 4)$[/tex]



Answer :

To factor the expression [tex]\( 40x^2 - 10 \)[/tex], follow these steps:

1. First, look for any common factors in the terms of the expression. Here, both terms [tex]\( 40x^2 \)[/tex] and [tex]\( 10 \)[/tex] have a common factor of 10. So, we can factor out 10:
[tex]\[ 40x^2 - 10 = 10(4x^2 - 1) \][/tex]

2. Next, observe that [tex]\( 4x^2 - 1 \)[/tex] is a difference of squares. We know the formula for the difference of squares is:
[tex]\[ a^2 - b^2 = (a - b)(a + b) \][/tex]

3. Rewrite [tex]\( 4x^2 - 1 \)[/tex] in the form [tex]\( a^2 - b^2 \)[/tex]:
[tex]\[ 4x^2 - 1 = (2x)^2 - 1^2 \][/tex]

4. Apply the difference of squares formula:
[tex]\[ (2x)^2 - 1^2 = (2x - 1)(2x + 1) \][/tex]

5. Substitute back into the expression where we factored out the 10:
[tex]\[ 40x^2 - 10 = 10(2x - 1)(2x + 1) \][/tex]

Therefore, the factored form of the expression [tex]\( 40x^2 - 10 \)[/tex] is:
[tex]\[ 10(2x - 1)(2x + 1) \][/tex]

Since none of the provided answer choices match exactly with our factored form at first glance, let's ensure there isn't simplification or a different representation that matches. After confirming, the correct answer is:

[tex]\(\boxed{None of the above}\)[/tex]

(Note: Given the provided choices A, B, C, and D, and verifying the detailed factorization steps, none of these match the correct factorization of [tex]\( 40x^2 - 10 \)[/tex]. If this is not the expected final answer, there might be an error or need for reconsideration in the provided options.)