document.write( "Question 119166: A BATTER HITS A PITCHED BASEBALL WHEN IT IS 3 FEET OFF THE GROUND. AFTER IT IS HIT THE HEIGHT (IN FEET) OF THE BALL IS MODELED BY H=-16T^2+80T+3 WHERE T IS THE TIME ( IN SECONDS). HOW LONG WILL IT TAKE THE BALL TO HIT THE GROUND? ROUND TO THE NEAREST HUNDEREDTH. H= 0. MAKE SURE THIS EQUATION IS IN STANDARD FORM. \n" ); document.write( "
Algebra.Com's Answer #87269 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
The ball will hit the ground when h=0\r
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\n" ); document.write( "\n" ); document.write( "\"h=-16t%5E2%2B80t%2B3\" Start with the given equation\r
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\n" ); document.write( "\n" ); document.write( "\"0=-16t%5E2%2B80t%2B3\" Plug in h=0\r
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\n" ); document.write( "\n" ); document.write( "Let's use the quadratic formula to solve for t:\r
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\n" ); document.write( "\n" ); document.write( "Starting with the general quadratic\r
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\n" ); document.write( "\n" ); document.write( "\"at%5E2%2Bbt%2Bc=0\"\r
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\n" ); document.write( "\n" ); document.write( "the general solution using the quadratic equation is:\r
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\n" ); document.write( "\n" ); document.write( "\"t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29\"\r
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\n" ); document.write( "\n" ); document.write( "So lets solve \"-16%2At%5E2%2B80%2At%2B3=0\" ( notice \"a=-16\", \"b=80\", and \"c=3\")\r
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\n" ); document.write( "\n" ); document.write( "\"t+=+%28-80+%2B-+sqrt%28+%2880%29%5E2-4%2A-16%2A3+%29%29%2F%282%2A-16%29\" Plug in a=-16, b=80, and c=3\r
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\n" ); document.write( "\n" ); document.write( "\"t+=+%28-80+%2B-+sqrt%28+6400-4%2A-16%2A3+%29%29%2F%282%2A-16%29\" Square 80 to get 6400 \r
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\n" ); document.write( "\n" ); document.write( "\"t+=+%28-80+%2B-+sqrt%28+6400%2B192+%29%29%2F%282%2A-16%29\" Multiply \"-4%2A3%2A-16\" to get \"192\"\r
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\n" ); document.write( "\n" ); document.write( "\"t+=+%28-80+%2B-+sqrt%28+6592+%29%29%2F%282%2A-16%29\" Combine like terms in the radicand (everything under the square root)\r
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\n" ); document.write( "\n" ); document.write( "\"t+=+%28-80+%2B-+8%2Asqrt%28103%29%29%2F%282%2A-16%29\" Simplify the square root (note: If you need help with simplifying the square root, check out this solver)\r
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\n" ); document.write( "\n" ); document.write( "\"t+=+%28-80+%2B-+8%2Asqrt%28103%29%29%2F-32\" Multiply 2 and -16 to get -32\r
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\n" ); document.write( "\n" ); document.write( "So now the expression breaks down into two parts\r
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\n" ); document.write( "\n" ); document.write( "\"t+=+%28-80+%2B+8%2Asqrt%28103%29%29%2F-32\" or \"t+=+%28-80+-+8%2Asqrt%28103%29%29%2F-32\"\r
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\n" ); document.write( "\n" ); document.write( "Now break up the fraction\r
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\n" ); document.write( "\n" ); document.write( "\"t=-80%2F-32%2B8%2Asqrt%28103%29%2F-32\" or \"t=-80%2F-32-8%2Asqrt%28103%29%2F-32\"\r
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\n" ); document.write( "\n" ); document.write( "Simplify\r
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\n" ); document.write( "\n" ); document.write( "\"t=5+%2F+2-sqrt%28103%29%2F4\" or \"t=5+%2F+2%2Bsqrt%28103%29%2F4\"\r
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\n" ); document.write( "\n" ); document.write( "So these expressions approximate to\r
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\n" ); document.write( "\n" ); document.write( "\"t=-0.0372228912730548\" or \"t=5.03722289127306\"\r
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\n" ); document.write( "\n" ); document.write( "So our possible solutions are:\r
\n" ); document.write( "\n" ); document.write( "\"t=-0.0372228912730548\" or \"t=5.03722289127306\"\r
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\n" ); document.write( "\n" ); document.write( "However, since a negative time doesn't make sense, our only solution is \"t=5.03722289127306\"\r
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\n" ); document.write( "\n" ); document.write( "So it takes about 5.03 seconds for the ball to hit the ground.
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