document.write( "Question 1181268: Word Problem Help\r
\n" ); document.write( "\n" ); document.write( "A ball is thrown from an initial height of 4 feet with an initial upward velocity of 31 ft/s. The ball's height h (in feet) after t seconds is given by the following.\r
\n" ); document.write( "\n" ); document.write( "\"+h=4%2B31t-16t%5E2+\"\r
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\n" ); document.write( "\n" ); document.write( "Find all values of for which the ball's height is 18 feet.
\n" ); document.write( "Round your answer(s) to the nearest hundredth.
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Algebra.Com's Answer #811131 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "if \"h=18\" feet\r
\n" ); document.write( "\n" ); document.write( "\"+18=4%2B31t-16t%5E2+\".......solve for \"t\"\r
\n" ); document.write( "\n" ); document.write( "\"+0=-18%2B4%2B31t-16t%5E2+\"
\n" ); document.write( "\"+0=-14%2B31t-16t%5E2+\"
\n" ); document.write( "\"+0=-16t%5E2%2B31t+-14\"\r
\n" ); document.write( "\n" ); document.write( "use quadratic formula to calculate \"t\"\r
\n" ); document.write( "\n" ); document.write( "\"t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\".....you have \"a=-16\",\"b=31\",\"c=-14\"\r
\n" ); document.write( "\n" ); document.write( "\"t+=+%28-31+%2B-+sqrt%28+31%5E2-4%2A%28-16%29%2A%28-14%29+%29%29%2F%282%2A%28-16%29%29+\"\r
\n" ); document.write( "\n" ); document.write( "\"t+=+%28-31+%2B-+sqrt%28+961-896+%29%29%2F%28-32%29+\"\r
\n" ); document.write( "\n" ); document.write( "\"t+=+%28-31+%2B-+sqrt%28+65+%29%29%2F%28-32%29+\"\r
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\n" ); document.write( "\n" ); document.write( "solutions:\r
\n" ); document.write( "\n" ); document.write( "\"t+=+%28-31+%2B+sqrt%28+65+%29%29%2F%28-32%29+\"=>\"t+=31%2F32+-+sqrt%28+65+%29%2F32+\"=>\"t=0.72\"
\n" ); document.write( "\"t+=+%28-31+-+sqrt%28+65+%29%29%2F%28-32%29+\"=> \"t+=+31%2F32+%2B+sqrt%28+65+%29%2F32+\"=>\"t=1.22\"\r
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