SOLUTION: Subtract the fractions. Express the answer in simplest form: [(5a-12)/(a^2-8a+15)]-[(3a-2)/(a^2-8a+15)]

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equation Customizable Word Problems -> SOLUTION: Subtract the fractions. Express the answer in simplest form: [(5a-12)/(a^2-8a+15)]-[(3a-2)/(a^2-8a+15)]      Log On


   



Question 147315: Subtract the fractions. Express the answer in simplest form:
[(5a-12)/(a^2-8a+15)]-[(3a-2)/(a^2-8a+15)]

Answer by Electrified_Levi(103) About Me  (Show Source):
You can put this solution on YOUR website!
Hi, Hope I can help.
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This problem is pretty easy, once you know how to do it.
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+%28%285a-12%29%2F%28a%5E2-8a%2B15%29%29-%28%283a-2%29%2F%28a%5E2-8a%2B15%29%29+
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First you have to combine like terms. You don't have to do anything with the bottom number yet, because both bottom numbers are the same. You have to get rid of your parentheses. You can subtract now( same bottom numbers).
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It becomes +%28%285a-12%29-+%283a-2%29%29%2F%28a%5E2-8a%2B15%29%29+
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Next, you get rid of the parentheses.
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It becomes
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+%28+5a-12-3a%2B2%29%2F%28a%5E2-8a%2B15%29+ (Two negatives make a positive)
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Now combine terms,
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It becomes
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+%285a+-+3a+-+12+%2B+2%29%2F%28a%5E2-8a%2B15%29+
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Now solve, It becomes
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+%282a+-+10%29%2F+%28a%5E2-8a%2B15%29+
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Now you need to reduce it, It will be
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+%282%28a+-+5%29%29%2F+%28%28a+-+5%29%28a+-+3%29%29+
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It reduces to +2+%2F+%28a+-+3%29+, your answer
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You can check by putting almost any number in place of "a"
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+%28%285a-12%29%2F%28a%5E2-8a%2B15%29%29-%28%283a-2%29%2F%28a%5E2-8a%2B15%29%29+
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Let's use "10"
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it = +%28%2850-12%29%2F%28100-80%2B15%29%29+-+%28%2830-2%29%2F%28100-80%2B15%29%29+
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it = +%2838%29%2F%2835%29%29+-+%28%2828%2F35%29%29+
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it = +%2810%2F35%29+, or +%282%2F7%29+, our answer +2%2F%28a-3%29+ works (our "a" was 10, so +%282%2F%2810-3%29%29+ = +%282%2F7%29+
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Sometimes it will work for only one number so we will use another number and see if it works again.
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We will use "7" for our "a"
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+%28%285a-12%29%2F%28a%5E2-8a%2B15%29%29-%28%283a-2%29%2F%28a%5E2-8a%2B15%29%29+
=

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+%28%2835-12%29%2F%2849-56%2B15%29%29-%28%2821-2%29%2F%2849-56%2B15%29%29+
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+%2823%2F8%29-%2819%2F8%29+
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%284%2F8%29, or +%281%2F2%29+
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our answer +2%2F%28a-3%29%29+ (our "a" was 7)
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+%282%2F%287-3%29%29+ or +%282%2F4%29+, same as +%281%2F2%29+ (both = 0.5)
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I also tried "a" as 43, it also worked
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The answer is +2%2F%28a-3%29+
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Hope I helped, Levi