document.write( "Question 683924: h = –16t2 + 40t + 8.
\n" ); document.write( "The height h in feet of an object after t seconds is given by the function
\n" ); document.write( " h = –16t2 + 40t + 8.
\n" ); document.write( "How long will it take the object to hit the ground? Round your answer to the nearest thousandth.
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Algebra.Com's Answer #423819 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
It reaches the ground when $\"+h+=+0+\"$
\n" ); document.write( " $\"+h+=+-16t%5E2+%2B+40t+%2B+8+\"$
\n" ); document.write( " $\"+0+=+-16t%5E2+%2B+40t+%2B+8+\"$
\n" ); document.write( " $\"+0+=+-2t%5E2+%2B+5t+%2B+1+\"$
\n" ); document.write( "Use the quadratic formula:
\n" ); document.write( " $\"+t+=+%28-b+%2B-+sqrt%28+b%5E2+-+4%2Aa%2Ac+%29%29+%2F+%282%2Aa%29+\"$
\n" ); document.write( " $\"+a+=+-2+\"$
\n" ); document.write( " $\"+b+=+5+\"$
\n" ); document.write( " $\"+c+=+1+\"$
\n" ); document.write( " $\"+t+=+%28-5+%2B-+sqrt%28+5%5E2+-+4%2A%28-2%29%2A1+%29%29+%2F+%282%2A%28-2%29%29+\"$
\n" ); document.write( " $\"+t+=+%28-5+%2B-+sqrt%28+25+%2B+8+%29%29+%2F+%28-4%29+\"$
\n" ); document.write( " $\"+t+=+%28-5+%2B-+sqrt%28+33+%29%29+%2F+%28-4%29+\"$
\n" ); document.write( " $\"+t+=+5%2F4+%2B+sqrt%2833%29%2F4+\"$
\n" ); document.write( " $\"+t+=+1.25+%2B+5.7446%2F4+\"$
\n" ); document.write( " $\"+t+=+1.25+%2B+1.4362+\"$
\n" ); document.write( " $\"+t+=+2.686+\"$ sec
\n" ); document.write( "Here's a plot of the function:
\n" ); document.write( " $\"+graph%28+400%2C+400%2C+-2%2C+4%2C+-1%2C+5%2C++-2x%5E2+%2B+5x+%2B+1+%29+\"$
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