SOLUTION: To solve 1/x-3+ 1/x+3 = 10/x^2-9, which step would result? I got: (x+3)+(x+3) = 10 Is this correct? Thanks~

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: To solve 1/x-3+ 1/x+3 = 10/x^2-9, which step would result? I got: (x+3)+(x+3) = 10 Is this correct? Thanks~      Log On


   



Question 79700: To solve 1/x-3+ 1/x+3 = 10/x^2-9, which step would result?
I got: (x+3)+(x+3) = 10
Is this correct?
Thanks~

Answer by bucky(2189) About Me  (Show Source):
You can put this solution on YOUR website!
Given:
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1%2F%28x-3%29+%2B++1%2F%28x%2B3%29+=+10%2F%28x%5E2-9%29
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Don't think you are correct, but let's check your answer. You got:
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%28x%2B3%29%2B%28x%2B3%29+=+10
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Remove the parentheses and this becomes:
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x+%2B+3++%2B+x+%2B+3+=+10
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Add like terms on the left side and you get:
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2x+%2B+6+=+10
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Subtract 6 from both sides and you get:
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2x+=+4
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Then divide both sides by 2 and you finally have x+=+2. If you return to the
original equation and substitute 2 for x it becomes:
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1%2F%282-3%29%2B1%2F%282%2B3%29+=+10%2F%282%5E2+-9%29
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Doing the math in the 3 denominators results in:
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1%2F%28-1%29+%2B+1%2F5+=+10%2F%284-9%29
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and this further simplifies to:
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-1+%2B++1%2F5+=+10%2F-5
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which becomes:
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-1+%2B+1%2F5+=+-2
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by adding +1 to both sides this becomes:
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%2B1%2F5+=+-1
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That doesn't look too good.
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Let's go back to the original problem and work it out:
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1%2F%28x-3%29+%2B++1%2F%28x%2B3%29+=+10%2F%28x%5E2-9%29
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You probably recognized that the denominator on the right side factors to:
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%28x-3%29%2A%28x%2B3%29
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Substitute that into the equation and it becomes:
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1%2F%28x-3%29+%2B++1%2F%28x%2B3%29+=+10%2F%28%28x-3%29%28x%2B3%29%29
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Now multiply all the terms on both sides by %28x-3%29%28x%2B3%29. When you do it becomes:
.

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cross out the common terms in the denominator and the numerator:
.

.
and the equation becomes:
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%28x%2B3%29+%2B+%28x-3%29+=+10
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Remove the parentheses:
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x+%2B+3+%2B+x+-+3+=+10
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Combine the like terms on the left side (note +3 -3 = 0) and you get:
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2x+=+10
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Finally divide both sides by 2 and you get:
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x+=+5
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Now let's check the answer. Return to the original equation and substitute 5 for x to get:
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1%2F%28x-3%29+%2B++1%2F%28x%2B3%29+=+10%2F%28x%5E2-9%29
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1%2F%285-3%29+%2B++1%2F%285%2B3%29+=+10%2F%285%5E2-9%29
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1%2F2+%2B+1%2F8+=+10%2F%2825-9%29
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4%2F8+%2B+1%2F8+=+10%2F16
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5%2F8+=+10%2F16
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5%2F8+=+5%2F8
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That works ... so the answer is x = 5
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Hope this helps you to find your mistake.