document.write( "Question 131739: Could you please explain to me how to find the vertex of the parabola given by: y= -2x^2 -3x + 8 ? \n" ); document.write( "

Algebra.Com's Answer #96172 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
The vertex is at $\"x+=+%28-b%29%2F%282a%29\"$
\n" ); document.write( "where the equation is in the form
\n" ); document.write( " $\"y+=+ax%5E2+%2B+bx+%2B+c\"$
\n" ); document.write( "Your equation is:
\n" ); document.write( " $\"y+=+-2x%5E2+-+3x+%2B+8\"$
\n" ); document.write( " $\"a+=+-2\"$
\n" ); document.write( " $\"b+=+-3\"$
\n" ); document.write( " $\"c+=+8\"$
\n" ); document.write( " $\"%28-b%29%2F%282a%29+=+%28-%28-3%29%29%2F%282%2A%28-2%29%29\"$
\n" ); document.write( " $\"%28-b%29%2F%282a%29+=+-%283%2F4%29\"$
\n" ); document.write( " $\"x+=+-%283%2F4%29\"$
\n" ); document.write( "Now I have to find $\"y\"$
\n" ); document.write( " $\"y+=+-2%2A%28-%283%2F4%29%29%5E2+-+3%2A%28-%283%2F4%29%29+%2B+8\"$
\n" ); document.write( " $\"y+=+-%2818%2F16%29+%2B+9%2F4+%2B+8\"$
\n" ); document.write( " $\"y+=+-%289%2F8%29+%2B+18%2F8+%2B+64%2F8\"$
\n" ); document.write( " $\"y+=+73%2F8\"$
\n" ); document.write( "The vertex is at (-3/4 , 73/8)
\n" ); document.write( "I'll plot this to check
\n" ); document.write( " $\"+graph%28+600%2C+600%2C+-4%2C+4%2C+-4%2C+12%2C+-2x%5E2+-+3x+%2B+8%29+\"$ \n" ); document.write( "

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