careless850
Harry is trying to solve the equation y = 2x^2 − x − 6 using the quadratic formula. He has made an error in one of the steps below. Find the step where Harry went wrong.
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careless850
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apoorvk
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First of all, do you know what the quadratic formula is?
careless850
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Yes.
careless850
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I wrote this problem out 6 times, still can't see WHERE he went wrong.
apoorvk
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What are you corresponding 'a', 'b' and 'c' for this quadratic when you compare it with the standard equation of a quadratic "ax^2 + bx +c=0"?
careless850
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A = 2. B = -1. C = -6.
careless850
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\[1 \pm \sqrt{-1^{2}} - 4*2*-6\]
careless850
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-12 * -4 = 48.
1*1 = 1. \[1 \pm \sqrt{1-48 } \div 2\]
careless850
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So it would be
careless850
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Step 3?
careless850
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STEP 2!!!
careless850
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He + instead of -.
apoorvk
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Should be :
\[x = \frac{-(-1) \pm \sqrt{(-1)^2 - 4 \times 3 \times (-6) }{} }{2\times 2 }\]
careless850
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No, it'd be -6.
careless850
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-4 * 2 * -6.
apoorvk
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actually the second step itself ha the error.
(-1)^2 = 1
and yes that would be -4*2*-6 --> typo my bad.
apoorvk
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*has
careless850
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So, it's step 2, right?
apoorvk
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Yup!
careless850
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I have one more question.
apoorvk
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And please ask questions in the correct subject forum :)
apoorvk
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Sure, just post it as a new one!
careless850
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Oh wow, I didn't realize I was in biology