document.write( "Question 111570: i need help solve 2x^2-3x-2=0 using the quadratic formula \n" ); document.write( "
Algebra.Com's Answer #81366 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
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Solved by pluggable solver: Quadratic Formula
Let's use the quadratic formula to solve for x:

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\n" ); document.write( " Starting with the general quadratic
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\n" ); document.write( " \"ax%5E2%2Bbx%2Bc=0\"
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\n" ); document.write( " the general solution using the quadratic equation is:
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\n" ); document.write( " \"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29\"
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\n" ); document.write( " So lets solve \"2%2Ax%5E2-3%2Ax-2=0\" ( notice \"a=2\", \"b=-3\", and \"c=-2\")
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\n" ); document.write( " \"x+=+%28--3+%2B-+sqrt%28+%28-3%29%5E2-4%2A2%2A-2+%29%29%2F%282%2A2%29\" Plug in a=2, b=-3, and c=-2
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\n" ); document.write( " \"x+=+%283+%2B-+sqrt%28+%28-3%29%5E2-4%2A2%2A-2+%29%29%2F%282%2A2%29\" Negate -3 to get 3
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\n" ); document.write( " \"x+=+%283+%2B-+sqrt%28+9-4%2A2%2A-2+%29%29%2F%282%2A2%29\" Square -3 to get 9 (note: remember when you square -3, you must square the negative as well. This is because \"%28-3%29%5E2=-3%2A-3=9\".)
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\n" ); document.write( " \"x+=+%283+%2B-+sqrt%28+9%2B16+%29%29%2F%282%2A2%29\" Multiply \"-4%2A-2%2A2\" to get \"16\"
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\n" ); document.write( " \"x+=+%283+%2B-+sqrt%28+25+%29%29%2F%282%2A2%29\" Combine like terms in the radicand (everything under the square root)
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\n" ); document.write( " \"x+=+%283+%2B-+5%29%2F%282%2A2%29\" Simplify the square root (note: If you need help with simplifying the square root, check out this solver)
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\n" ); document.write( " \"x+=+%283+%2B-+5%29%2F4\" Multiply 2 and 2 to get 4
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\n" ); document.write( " So now the expression breaks down into two parts
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\n" ); document.write( " \"x+=+%283+%2B+5%29%2F4\" or \"x+=+%283+-+5%29%2F4\"
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\n" ); document.write( " Lets look at the first part:
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\n" ); document.write( " \"x=%283+%2B+5%29%2F4\"
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\n" ); document.write( " \"x=8%2F4\" Add the terms in the numerator
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\n" ); document.write( " \"x=2\" Divide
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\n" ); document.write( " So one answer is
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\n" ); document.write( " \"x=2\"
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\n" ); document.write( " Now lets look at the second part:
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\n" ); document.write( " \"x=%283+-+5%29%2F4\"
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\n" ); document.write( " \"x=-2%2F4\" Subtract the terms in the numerator
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\n" ); document.write( " \"x=-1%2F2\" Divide
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\n" ); document.write( " So another answer is
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\n" ); document.write( " \"x=-1%2F2\"
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\n" ); document.write( " So our solutions are:
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\n" ); document.write( " \"x=2\" or \"x=-1%2F2\"
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