Mathematics
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OpenStudy (anonymous):
factor completely
a^4c^4 - 81
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OpenStudy (anonymous):
meant a^4x^4- 81
OpenStudy (mertsj):
Do you recognize this as the differrence of 2 squares?
OpenStudy (anonymous):
a^2 - b^2 = (a + b)(a - b)
OpenStudy (anonymous):
yes
OpenStudy (anonymous):
a^4x^4 - 81 = (a^2x^2 - 9)(a^2x^2 + 9)
can it be factored further - i'm looking at the first bracket
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OpenStudy (anonymous):
no
OpenStudy (anonymous):
Hint: 9 = 3^2
OpenStudy (mertsj):
Are you with me so far?
OpenStudy (anonymous):
yes
OpenStudy (mertsj):
Correction:
\[a^4x^4-81=[(a^2x^2)^2-9^2]=(a^2x^2-9)(a^2x^2+9)\]
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OpenStudy (anonymous):
\[a ^{2}x ^{2} = (ax)^{2} and 9 = 3^{2}\]
OpenStudy (anonymous):
Does that help?
OpenStudy (mertsj):
So now please note that \[a^2x^2-9 \] is also the difference of two squares and can be factored again.
OpenStudy (anonymous):
alright
OpenStudy (mertsj):
\[a^2x^2-9=(ax-3)(ax+3)\]
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OpenStudy (mertsj):
Still with me?
OpenStudy (anonymous):
yes
OpenStudy (anonymous):
That's it, that's the answer:
\[(ax + 3)(ax + 3)(a ^{2}x ^{2} + 9) \]
OpenStudy (mertsj):
So we now have the following for the completely factored form:
\[(ax-3)(ax+3)(a^2x^2+9)\]
OpenStudy (anonymous):
Thank you!
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OpenStudy (mertsj):
And, of course, the answer pratu posted is incorrect.
OpenStudy (mertsj):
yw. Do you understand?
OpenStudy (anonymous):
can you please give the best answer thing to pratu043 since i cant ?
OpenStudy (anonymous):
Sorry, its ax - 3
OpenStudy (anonymous):
alright & yes i understand thanks!
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OpenStudy (anonymous):
You don't need to I gave the wrong answer.
OpenStudy (anonymous):
Thanks anyway.