document.write( "Question 212927: I need to solve this by factoring but can't seem to get it!\r
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document.write( "Suppose the altitude of a rising hot air balloon is given by h=0.04t^2+2t where \"t\" is the time in seconds afer the balloon leaves the ground. How long will it take for the balloon to reach an altitude of 200 ft.?\r
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document.write( "Thanks for the help!
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Algebra.Com's Answer #160850 by rapaljer(4671)![]() ![]() You can put this solution on YOUR website! First, substitute the height of 200 feet for h in the equation:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "200=0.04t^2 +2t\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since it's a quadratic equation, set it equal to zero by subtracting 200 from each side:\r \n" ); document.write( "\n" ); document.write( "0=0.04t^2 + 2t -200\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Next I would get rid of that ugly decimal by multiplying both sides by 100: \n" ); document.write( "0= 4t^2 + 200t - 20000\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Divide both sides by 4: \n" ); document.write( "0=t^2 + 50t -5000\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Next, to solve by factoring you must find two numbers with opposite sign whose product is 5000 (actually -5000!) and whose difference is 50 (to give you the middle term of +50t). The first combination of numbers that came to mind for me was 50*100. That's the one!!\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "0=(t+100)(t-50)\r \n" ); document.write( "\n" ); document.write( "t=-100 or t=50\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Reject the negative answer, since time cannot be negative, and the answer must be t=50 sec.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "R^2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Dr. Robert J. Rapalje \n" ); document.write( "Seminole Community College \n" ); document.write( "Altamonte Springs Campus \n" ); document.write( " |