Factor completely 4x2 - 81.
(4x - 9)(x + 9)
(2x + 9)(2x + 9)
(2x + 9)(2x - 9)
(2x - 9)(2x - 9)

Question

Factor completely 4x2 - 81.
 (4x - 9)(x + 9) 
(2x + 9)(2x + 9)
 (2x + 9)(2x - 9) 
(2x - 9)(2x - 9)

anonymous · Answer

I don't understand what you are trying to do here. Are you trying to get the answer for each math problem?

anonymous · Answer

no this isn't even on the same thing

nnesha · Answer

apply difference of square method  $$\huge\rm (a^2 - b^2) = (a-b)(a+b)$$

jpes2193 · Answer

so its (2x+9)(2x-9)

anonymous · Answer

that's what I thought but I don't wanna get it wrong

nnesha · Answer

how  ??

anonymous · Answer

because a negative times a positive is a negative and 4x times x is 4x^2

nnesha · Answer

|dw:1428857167121:dw|
take square root of first term and take square root of 2nd term
one parentheses should be negative and one should be positive