document.write( "Question 46660: The equation h=-16t^2-32t+320 gives the height od a ball, thrown downward from the top of a 320-ft building with an initial velocity of 32ft/s. Find the time it takes for the ball to reach a height of 64ft. \n" ); document.write( "

Algebra.Com's Answer #30905 by Nate(3500) $\"\"$ $\"About$

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$\"h+=+-16t%5E2+-+32t+%2B+320\"$
\n" ); document.write( " $\"64+=+-16t%5E2+-+32t+%2B+320\"$
\n" ); document.write( " $\"0+=+-16t%5E2+-+32t+%2B+256\"$
\n" ); document.write( " $\"0+=+t%5E2+%2B+2t+-+16\"$
\n" ); document.write( " $\"x+=+%28-b+%2B-+sqrt%28+b%5E2+-+4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"$
\n" ); document.write( " $\"x+=+%28-2+%2B-+sqrt%28+4+%2B+64+%29%29%2F%282%29+\"$
\n" ); document.write( " $\"x+=+-1+%2B-+sqrt%28+17+%29+\"$ \n" ); document.write( "

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