SOLUTION: factor the polynomial completely 121rSQUARED-64tSQUARED

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Question 80883: factor the polynomial completely
121rSQUARED-64tSQUARED

Found 2 solutions by sofiyacherni, bucky:
Answer by sofiyacherni(99) About Me  (Show Source):
You can put this solution on YOUR website!
(11r-8t)(11r+8t)

Answer by bucky(2189) About Me  (Show Source):
You can put this solution on YOUR website!
Given:
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121r%5E2+-+64t%5E2
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The problem is to factor this expression.
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The given expression contains the difference of two perfect squares. As such it falls under
the factoring rule:
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a%5E2+-+b%5E2%29+=+%28a-b%29%2A%28a%2Bb%29
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By comparing this rule with the given expression you can see that:
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a%5E2+=+121r%5E2
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and this leads to a+=+sqrt%28121r%5E2%29+=+11r
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Similarly:
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b%5E2+=+64t%5E2
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and taking the square root of both sides of this results in:
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b+=+sqrt%2864t%5E2%29+=+8t
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Now return to the factoring rule and substitute for a and b using the above expressions.
When you do you get:
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%28%2811r%29%5E2+-+%288t%29%5E2%29+=+%2811r+-+8t%29%2A%2811r+%2B+8t%29
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and the right side of this equation is the answer you are looking for.
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Hope this helps you become familiar with the factoring rule for the difference between
squares. It comes up reasonably often in book problems that you need to be aware of it, and
the more you see and use it, the more you will tend to remember it.
.
Cheers ...