document.write( "Question 184401: at what points does the graph of y=2x^2-4x-16 intersect the x-axis? \n" ); document.write( "

Algebra.Com's Answer #138406 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
The graph crosses the x-axis wherever $\"y=0\"$
\n" ); document.write( "Set $\"y+=+o\"$
\n" ); document.write( " $\"2x%5E2+-+4x+-+16+=+0\"$
\n" ); document.write( "Use quadratic formula with $\"ax%5E2+%2B+bx+%2B+c+=+0\"$
\n" ); document.write( " $\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"$
\n" ); document.write( " $\"a+=+2\"$
\n" ); document.write( " $\"b+=+-4\"$
\n" ); document.write( " $\"c+=+-16\"$
\n" ); document.write( " $\"x+=+%28-%28-4%29+%2B-+sqrt%28+%28-4%29%5E2-4%2A2%2A%28-16%29+%29%29%2F%282%2A2%29+\"$
\n" ); document.write( " $\"x+=+%284+%2B-+sqrt%28+16+%2B+128+%29%29%2F4+\"$
\n" ); document.write( " $\"x+=+%284+%2B-+sqrt%28+144+%29%29%2F4+\"$
\n" ); document.write( " $\"x+=+%284+%2B-+12%29%2F4+\"$
\n" ); document.write( " $\"x+=+%284+%2B+12%29%2F4\"$
\n" ); document.write( " $\"x+=+4\"$
\n" ); document.write( "and
\n" ); document.write( " $\"x+=+4+-+12%29%2F4\"$
\n" ); document.write( " $\"x+=+-2\"$
\n" ); document.write( "the graph crosses the x-axis at $\"x+=+-2\"$ and $\"x+=+4\"$
\n" ); document.write( "Here's a plot:
\n" ); document.write( " $\"+graph%28+500%2C+500%2C+-4%2C+7%2C+-18%2C+4%2C+2x%5E2+-+4x+-+16%29+\"$
\n" ); document.write( " \n" ); document.write( "

\n" );