document.write( "Question 101192: 4x^2+2x-3=0. Solve by completing the square. (4x^2 is 4x squared) \n" ); document.write( "
Algebra.Com's Answer #73649 by jim_thompson5910(35256)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "\"4x%5E2%2B2x-3=0\" Start with the given equation\r
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\n" ); document.write( "\n" ); document.write( "\"4x%5E2%2B2x=3\" Add 3 to both sides
\n" ); document.write( "\"4%28x%5E2%2B0.5x%29=3\" Factor out the leading coefficient 4. This step is important since we want the \"x%5E2\" coefficient to be equal to 1.\r
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\n" ); document.write( "\n" ); document.write( "Take half of the x coefficient 0.5 to get 0.25 (ie \"0.5%2F2=0.25\")\r
\n" ); document.write( "\n" ); document.write( "Now square 0.25 to get 0.0625 (ie \"%280.25%29%5E2=0.0625\")\r
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\n" ); document.write( "\n" ); document.write( "\"4%28x%5E2%2B0.5x%2B0.0625%29=3%2B0.0625%284%29\" Add this result (0.0625) to the expression \"x%5E2%2B0.5x\" inside the parenthesis. Now the expression \"x%5E2%2B0.5x%2B0.0625\" is a perfect square trinomial. Now add the result (0.0625)(4) (remember we factored out a 4) to the right side.\r
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\n" ); document.write( "\n" ); document.write( "\"4%28x%2B0.25%29%5E2=3%2B0.0625%284%29\" Factor \"x%5E2%2B0.5x%2B0.0625\" into \"%28x%2B0.25%29%5E2\" \r
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\n" ); document.write( "\n" ); document.write( "\"4%28x%2B0.25%29%5E2=3%2B0.25\" Multiply 0.0625 and 4 to get 0.25\r
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\n" ); document.write( "\n" ); document.write( "\"4%28x%2B0.25%29%5E2=3.25\" Combine like terms on the right side\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B0.25%29%5E2=0.8125\" Divide both sides by 4\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B0.25=0%2B-sqrt%280.8125%29\" Take the square root of both sides\r
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\n" ); document.write( "\n" ); document.write( "\"x=-0.25%2B-sqrt%280.8125%29\" Subtract 0.25 from both sides to isolate x.\r
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\n" ); document.write( "\n" ); document.write( "So the expression breaks down to\r
\n" ); document.write( "\n" ); document.write( "\"x=-0.25%2Bsqrt%280.8125%29\" or \"x=-0.25-sqrt%280.8125%29\"\r
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\n" ); document.write( "\n" ); document.write( "So our answer is approximately\r
\n" ); document.write( "\n" ); document.write( "\"x=0.651387818865997\" or \"x=-1.151387818866\"\r
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\n" ); document.write( "\n" ); document.write( "Here is visual proof\r
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\n" ); document.write( "\n" ); document.write( "\"+graph%28+500%2C+500%2C+-10%2C+10%2C+-10%2C+10%2C+4x%5E2%2B2x-3%29+\" graph of \"y=4x%5E2%2B2x-3\"\r
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\n" ); document.write( "\n" ); document.write( "When we use the root finder feature on a calculator, we would find that the x-intercepts are \"x=0.651387818865997\" and \"x=-1.151387818866\", so this verifies our answer.\r
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