SOLUTION: Find all solutions to the equation. r(squared)-8t=-15

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Question 110062: Find all solutions to the equation.
r(squared)-8t=-15

Answer by bucky(2189) About Me  (Show Source):
You can put this solution on YOUR website!
Given the equation:
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t%5E2+-8t+=+-15
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Begin by collecting all the terms on the left side of the equation and getting a zero on the
right side. You can do this by adding +15 to both sides to get:
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t%5E2+-8t+%2B+15+=+0
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Note that the left side of this equation factors and after factoring the equation becomes:
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%28t+-+5%29%2A%28t+-+3%29=+0
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This equation will be true if either of the two factors on the left side is equal to zero.
This is the case because multiplication by zero on the left side makes the entire left
side equal to zero ... and therefore, it is equal to the right side.
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So, one at a time, set the two factors equal to zero to solve for t.
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t+-+5+=+0
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Add 5 to both sides and you get:
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t+=+5
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Next:
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t+-+3+=+0
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Add 3 to both sides and you get:
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t+=+3
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The two answers to this problem are t = 5 and t = 3. Let's check them by returning to
the given equation, substituting these values, and seeing if the equation balances.
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Start with:
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t%5E2+-8t+=+-15
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First substitute 5 for t and the left side of the equation becomes:
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5%5E2+-+8%2A5+=+25+-+40+=+-15
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So when t = 5 the left side of the equation becomes -15 and this equals the right side.
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Next substitute 3 for t and the left side of the equation is:
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3%5E2+-+8%2A3+=+9+-+24+=+-15
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As before, when t = 3 the left side of the equation is -15 and this equals the right side.
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So we can conclude that t = 5 and t = 3 are the correct answers to this problem.
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Hope this helps you to understand this problem.
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