document.write( "Question 1178634: A ball is thrown straight up from a rooftop 432 feet high. The formula below describes the​ ball's height above the​ ground, h, in​ feet, t seconds after it was thrown. The ball misses the rooftop on its way down. The graph of the formula is shown. Determine when the​ ball's height will be 378 feet and identify the solution as a point on the graph.\r
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Algebra.Com's Answer #807963 by ikleyn(52786)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "To solve the problem and to get the answer, you need to solve this quadratic equation\r\n" );
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document.write( "    -16t^2 + 30t + 432 = 378.\r\n" );
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document.write( "Rewrite it in this equivalent form\r\n" );
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document.write( "    16t^2 - 30t - 54 = 0\r\n" );
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document.write( "Find the roots using the quadratic formula\r\n" );
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document.write( "    t = \"30+%2B-+sqrt%2830%5E2+%2B+4%2A16%2A54%29%29%2F%282%2A16%29\" = \"%2830+%2B-+sqrt%284356%29%29%2F32\" = \"%2830+%2B-+66%29%2F32\".\r\n" );
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document.write( "Only positive root  t = \"%2830%2B66%29%2F32\" = \"96%2F32\" = 3 seconds is the solution to the problem.\r\n" );
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\n" ); document.write( "\n" ); document.write( "In this site,  there is a bunch of lessons on a projectile thrown/shot/launched vertically up\r
\n" ); document.write( "\n" ); document.write( "    - Introductory lesson on a projectile thrown-shot-launched vertically up \r
\n" ); document.write( "\n" ); document.write( "    - Problem on a projectile moving vertically up and down\r
\n" ); document.write( "\n" ); document.write( "    - Problem on an arrow shot vertically upward\r
\n" ); document.write( "\n" ); document.write( "    - Problem on a ball thrown vertically up from the top of a tower \r
\n" ); document.write( "\n" ); document.write( "    - Problem on a toy rocket launched vertically up from a tall platform\r
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\n" ); document.write( "\n" ); document.write( "Consider these lessons as your textbook,  handbook,  tutorials and  (free of charge)  home teacher.
\n" ); document.write( "Read them attentively and learn how to solve this type of problems once and for all.\r
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\n" ); document.write( "\n" ); document.write( "Also,  you have this free of charge online textbook in ALGEBRA-I in this site\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this textbook under the topic \"Projectiles launched/thrown and moving vertically up and dawn\".\r
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\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
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