document.write( "Question 214986: I need help with sloving quadractic equations by factoring:
\n" ); document.write( "\"-2x%5E2%2B13x%2B7=0\"
\n" ); document.write( "

Algebra.Com's Answer #162448 by drj(1380)\"\" \"About 
You can put this solution on YOUR website!
I need help with sloving quadractic equations by factoring:\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-2x%5E2%2B13x%2B7=0\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Step 1. Multiply by -1 to get rid of negative in x-squared term.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"2x%5E2-13x-7=0\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Step 2. We need two integers m an n such that their products is n*m=-2*7=-14 and their sum n+m= -13.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "After several tries, these numbers are -14 and 1.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Step 3. Express -13x as -13x=-14x+1x=-14x+x and replace this in Step 1.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"2x%5E2-13x-7=%282x%5E2-14x%29%2B%28x-7%29\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Step 4. Factor out 2x in the first group with parenthesis\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"2x%5E2-13x-7=2x%28x-7%29%2B1%28x-7%29\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Step 5. Factor out x-7 common to the groups with parenthesis\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"2x%5E2-13x-7=%28x-7%29%282x%2B1%29=0\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Step 6. The above equation yields two solutions as follows:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x-7=0\" and \"2x%2B1=0\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=7\" and \"x=-1%2F2\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "As a check, let's use the quadratic formula given below and solve\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"ax%5E2%2Bbx%2Bc=0\" (in our case \"2x%5E2%2B-13x%2B-7+=+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=%28-13%29%5E2-4%2A2%2A-7=225\".
\n" ); document.write( "
\n" ); document.write( " Discriminant d=225 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28--13%2B-sqrt%28+225+%29%29%2F2%5Ca\".
\n" ); document.write( "
\n" ); document.write( " \"x%5B1%5D+=+%28-%28-13%29%2Bsqrt%28+225+%29%29%2F2%5C2+=+7\"
\n" ); document.write( " \"x%5B2%5D+=+%28-%28-13%29-sqrt%28+225+%29%29%2F2%5C2+=+-0.5\"
\n" ); document.write( "
\n" ); document.write( " Quadratic expression \"2x%5E2%2B-13x%2B-7\" can be factored:
\n" ); document.write( " \"2x%5E2%2B-13x%2B-7+=+2%28x-7%29%2A%28x--0.5%29\"
\n" ); document.write( " Again, the answer is: 7, -0.5.\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%2B-13%2Ax%2B-7+%29\"

\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Same result as before.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Step 7. ANSWER. The solutions are \"x=7\" and \"x=-1%2F2\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "I hope the above steps were helpful.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "For FREE Step-By-Step videos in Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra and for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Good luck in your studies!\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Respectfully,
\n" ); document.write( "Dr J\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );