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| Tweet Topic Started: Feb 18 2011, 07:49 PM (320 Views) | |
| Michelle | Feb 18 2011, 07:49 PM Post #1 |
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After I had clicked on "help me solve this" and finished it, I should have written down better instructions. The example was 6√27 - 2√18 + 75 Which equals 6√9 · 3 - 2√9 · 2 + 3√25 Which equals 6 · √9 · √3 - 2 · √9 · √2 + √25 · 3 Which equals 18 · √3 - 6 · √2 + 5√3 Which equals 18 · √3 - 6 · √2 + 5√3 Which equals 18√3 - 6√2 + 5√3 Which equals (18 + 5)√3 - 6√2 Which equals 23√3 - 6√2 Here's the question I'm on: 6√48 - 2√32 + √27 = 6√6 · 8 + 2√8 · 4 + 3√9 So yeah... I'm stuck on the third step
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| CJ | Feb 18 2011, 08:03 PM Post #2 |
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A very minor case of serious brain damage
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OK, so, we're starting with "6√48 - 2√32 + √27". What you need to do is re-write each of the numbers being square rooted as the product of two numbers, one of which should be a square number. So, 48 = 16 · 3; 32 = 16 · 2; 27 = 9 · 3. Substituting those in: 6√48 - 2√32 + √27 = 6√(16 · 3) - 2√(16 · 2) + √(9 · 3) Now, square roots distribute across multiplication: 6√(16 · 3) - 2√(16 · 2) + √(9 · 3) = 6(√16)(√3) - 2(√16)(√2) + (√9)(√3) But, √16 is just 4, and √9 is just 3: 6(√16)(√3) - 2(√16)(√2) + (√9)(√3) = 6 · 4√3 - 2 · 4√2 + 3√3 = 24√3 - 8√2 + 3√3 = 27√3 - 8√2 So, the answer is 27√3 - 8√2. Hope that helped! |
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| Michelle | Feb 18 2011, 08:13 PM Post #3 |
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It was right! Thank you so much! |
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| CJ | Feb 18 2011, 08:14 PM Post #4 |
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A very minor case of serious brain damage
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You're welcome . Just ask again if you need any more help.
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| Michelle | Feb 18 2011, 08:52 PM Post #5 |
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Okay. I will. I may reply again, if need be. |
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| CJ | Feb 18 2011, 08:59 PM Post #6 |
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A very minor case of serious brain damage
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In case it helps, here are some common ones: √8 = 2√2 √12 = 2√3 √18 = 3√2 √20 = 2√5 √27 = 3√3 √28 = 2√7 √32 = 4√2 √44 = 2√11 √45 = 3√5 √48 = 4√3 √50 = 5√2 |
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| Michelle | Feb 18 2011, 09:04 PM Post #7 |
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Umm thanks, I guess. |
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. Just ask again if you need any more help.
8:35 AM Jul 11