document.write( "Question 1130551: An object is launched from ground level directly upward at a rate of 144 feet per second. The equation for the object's height is h(x)=-16x^2+144x. What is the value of x, is the object at or above a height of 288 feet? How long is the object at or above this height? \n" ); document.write( "

Algebra.Com's Answer #747204 by ikleyn(52946) $\"\"$ $\"About$

You can put this solution on YOUR website!
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document.write( "-16x^2 + 144x = 288      (1)     ====>\r\n" );
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document.write( "16x^2 - 144x + 288 = 0  is equivalent to\r\n" );
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document.write( "x^2 - 9x + 18 = 0\r\n" );
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document.write( "(x-3)*(x-6) = 0.\r\n" );
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document.write( "The roots of the equation (1)  are  3  and  6  seconds.\r\n" );
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document.write( "So, the object is above the height of 144 ft  from  the time moment of 3 seconds till the time moment of 6 seconds,\r\n" );
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document.write( "or exactly  3 = 6 - 3 seconds.           ANSWER\r\n" );
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\n" ); document.write( "\n" ); document.write( "Solved.\r
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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( "    - 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( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\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( "\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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