Question

What is the product of (4x – 7)(4x + 7)?

Answer 1

$(4x - 7)(4x + 7)$
As you might've noticed that, it's in the form of
(a+b) (a-b)
where
a = 4x and b = 7


Now wherever an expression is in this form we use an alzebric identity to solve it. whichis as followed,
$(a + b)(a - b) = {a}^{2} - {b}^{2}$

Simply use that identity and we'll get

${(4x)}^{2} - {7}^{2} \\ = 16 {x}^{2} - 49$



Therefore option (D) is the correct answer.





Hope you got it.

Answer 2

Multiply using FOIL method (first, outside, inside, last)

=(4x – 7)(4x + 7)
=(4x * 4x) + (4x * 7) + (-7 * 4x) + (-7 * 7)
=16x^2 + 28x - 28x - 49
x term cancels out to zero
=16x^2 - 49

ANSWER: D) 16x^2 - 49

Hope this helps! :)