Westonci.ca is the Q&A platform that connects you with experts who provide accurate and detailed answers. Connect with a community of professionals ready to provide precise solutions to your questions quickly and accurately. Join our platform to connect with experts ready to provide precise answers to your questions in different areas.

Factor completely: 81x^4 – 1

A. (9x + 1)(9x – 1)
B. (9x^2 + 1)(9x^2 – 1)
C. (3x^2 + 1)^3(3x – 1)
D. (9x^2 + 1)(3x + 1)(3x – 1)


Sagot :

[tex]81x^4-1=\\ (9x^2)^2-1^2=\\ (9x^2+1)(9x^2-1)=\\ (9x^2+1)((3x)^2-1^2)=\\ (9x^2+1)(3x+1)(3x-1)[/tex]
eu99li


Using this: a²-b²=(a+b)(a-b)

81x^4-1=

(9x²)²-1=

(9x²-1)(9x²+1)=      (in the bold half we use the formula again)

(3x+1)(3x-1)(9x²+1)

So the answer is D