document.write( "Question 288295: I asked this problem earlier, but have learned how to type it so that it is easier for you to read and understand. I need to square this problem.
\n" ); document.write( "Problem: 2x^2+4x-1=0
\n" ); document.write( "Formula I used was: $\"%28-4%2B-sqrt%284%5E2-4%2A2%2A-1%29%29%2F%282%2A2%29\"$
\n" ); document.write( "I got:
\n" ); document.write( " $\"%28-4%2B-sqrt%2816-4%2A2%2A-1%29%29%2F%282%2A2%29\"$
\n" ); document.write( "then $\"%28-4%2B-sqrt%2816%2B8%29%29%2F%282%2A2%29\"$
\n" ); document.write( "then $\"%28-4%2B-sqrt%2824%29%29%2F%282%2A2%29\"$
\n" ); document.write( "then $\"%28-4%2B-2sqrt%286%29%29%2F%282%2A2%29\"$ (this is supposed to read \"+ or - 2\" not -2)
\n" ); document.write( "then $\"%28-4%2B-2sqrt%286%29%29%2F%284%29\"$ (this is supposed to read \"+ or - 2\", not -2)
\n" ); document.write( "then after simplifying, I get
\n" ); document.write( " $\"%28-1%2B-sqrt%286%29%29%2F%282%29\"$
\n" ); document.write( "My book says the answer is: $\"%28-2%2B-sqrt%286%29%29%2F%282%29\"$
\n" ); document.write( "I can't figure out where I went wrong, so I can't answer my real question of 2x^2+10x-3=0.
\n" ); document.write( "Any help is appreciated!! Thank you! \n" ); document.write( "

Algebra.Com's Answer #208961 by Alan3354(69443) $\"\"$ $\"About$

You can put this solution on YOUR website!
then $\"%28-4%2B-2sqrt%286%29%29%2F%284%29\"$ (this is supposed to read \"+ or - 2\", not -2)
\n" ); document.write( "then after simplifying, I get
\n" ); document.write( " $\"%28-1%2B-sqrt%286%29%29%2F%282%29\"$ **** This last step is not right ***
\n" ); document.write( "---------------------------
\n" ); document.write( "My book says the answer is: $\"%28-2%2B-sqrt%286%29%29%2F%282%29\"$
\n" ); document.write( "I can't figure out where I went wrong, so I can't answer my real question of 2x^2+10x-3=0.
\n" ); document.write( "-----------------
\n" ); document.write( "2x^2+10x-3=0
\n" ); document.write( "\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "

Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)

Quadratic equation $\"ax%5E2%2Bbx%2Bc=0\"$ (in our case $\"2x%5E2%2B10x%2B-3+=+0\"$ ) has the following solutons:
\n" ); document.write( "
\n" ); document.write( " $\"x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca\"$
\n" ); document.write( "
\n" ); document.write( " For these solutions to exist, the discriminant $\"b%5E2-4ac\"$ should not be a negative number.
\n" ); document.write( "
\n" ); document.write( " First, we need to compute the discriminant $\"b%5E2-4ac\"$ : $\"b%5E2-4ac=%2810%29%5E2-4%2A2%2A-3=124\"$ .
\n" ); document.write( "
\n" ); document.write( " Discriminant d=124 is greater than zero. That means that there are two solutions: $\"+x%5B12%5D+=+%28-10%2B-sqrt%28+124+%29%29%2F2%5Ca\"$ .
\n" ); document.write( "
\n" ); document.write( " $\"x%5B1%5D+=+%28-%2810%29%2Bsqrt%28+124+%29%29%2F2%5C2+=+0.283882181415011\"$
\n" ); document.write( " $\"x%5B2%5D+=+%28-%2810%29-sqrt%28+124+%29%29%2F2%5C2+=+-5.28388218141501\"$
\n" ); document.write( "
\n" ); document.write( " Quadratic expression $\"2x%5E2%2B10x%2B-3\"$ can be factored:
\n" ); document.write( " $\"2x%5E2%2B10x%2B-3+=+%28x-0.283882181415011%29%2A%28x--5.28388218141501%29\"$
\n" ); document.write( " Again, the answer is: 0.283882181415011, -5.28388218141501.\n" ); document.write( "Here's your graph:
\n" ); document.write( " $\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B10%2Ax%2B-3+%29\"$

\n" ); document.write( "\n" ); document.write( "---------------------
\n" ); document.write( "= (-5 ą sqrt(31))/2
\n" ); document.write( " \n" ); document.write( "

\n" );