document.write( "Question 456391: what is the answer to this problem: 4x^2 – 2x – 5 = 0 \n" ); document.write( "

Algebra.Com's Answer #313211 by richwmiller(17219) $\"\"$ $\"About$

You can put this solution on YOUR website!
Use the quadratic formula or complete the square to solve.
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Solved by pluggable solver: SOLVE quadratic equation with variable

Quadratic equation $\"ax%5E2%2Bbx%2Bc=0\"$ (in our case $\"4x%5E2%2B-2x%2B-5+=+0\"$ ) has the following solutons:
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\n" ); document.write( " $\"x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca\"$
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\n" ); document.write( " For these solutions to exist, the discriminant $\"b%5E2-4ac\"$ should not be a negative number.
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\n" ); document.write( " First, we need to compute the discriminant $\"b%5E2-4ac\"$ : $\"b%5E2-4ac=%28-2%29%5E2-4%2A4%2A-5=84\"$ .
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\n" ); document.write( " Discriminant d=84 is greater than zero. That means that there are two solutions: $\"+x%5B12%5D+=+%28--2%2B-sqrt%28+84+%29%29%2F2%5Ca\"$ .
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\n" ); document.write( " $\"x%5B1%5D+=+%28-%28-2%29%2Bsqrt%28+84+%29%29%2F2%5C4+=+1.39564392373896\"$
\n" ); document.write( " $\"x%5B2%5D+=+%28-%28-2%29-sqrt%28+84+%29%29%2F2%5C4+=+-0.89564392373896\"$
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\n" ); document.write( " Quadratic expression $\"4x%5E2%2B-2x%2B-5\"$ can be factored:
\n" ); document.write( " $\"4x%5E2%2B-2x%2B-5+=+4%28x-1.39564392373896%29%2A%28x--0.89564392373896%29\"$
\n" ); document.write( " Again, the answer is: 1.39564392373896, -0.89564392373896.\n" ); document.write( "Here's your graph:
\n" ); document.write( " $\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+4%2Ax%5E2%2B-2%2Ax%2B-5+%29\"$

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