document.write( "Question 1023619: Hi, basically could somebody show me the steps as to how the word problem below was turned into the equation? I want to know how the quadratic equation was made step by step? The equation is at the bottom after the word problem. Many thanks\r
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document.write( "\" TAHIR HAS A REGULAR CYCLE TRAINING ROUTE THAT IS 60KM LONG. IF TAHIR CYCLES 3KMH SLOWER THAN HIS RACING SPEED,IT TAKES HIM 3 HOURS AND 20 MINUTES LONGER TO COMPLETE THE ROUTE.\r
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document.write( "A) WORK OUT TAHIR'S RACING SPEED. STATE IN WORDS WHAT ALGEBRAIC METHOD YOU ARE USING AT EACH STAGE.\r
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document.write( "B) CHECK YOUR ANSWER BY USING TWO FURTHER ALTERNATIVE METHODS FOR SOLVING QUADRATIC EQUATIONS.\r
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document.write( "C) EVALUATE ALL THREE METHODS FOR EFFICIENCY AND EFFECTIVENESS.\r
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document.write( "V^2 - 3V - 54 = 0\r
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document.write( "TAHIR HAS A REGULAR CYCLE TRAINING ROUTE THAT IS 60KM LONG. IF TAHIR CYCLES 3KMH SLOWER THAN HIS RACING SPEED,IT TAKES HIM 3 HOURS AND 20 MINUTES LONGER TO COMPLETE THE ROUTE.\r
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document.write( "\n" );
document.write( "A) WORK OUT TAHIR'S RACING SPEED. STATE IN WORDS WHAT ALGEBRAIC METHOD YOU ARE USING AT EACH STAGE.\r
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document.write( "\n" );
document.write( "B) CHECK YOUR ANSWER BY USING TWO FURTHER ALTERNATIVE METHODS FOR SOLVING QUADRATIC EQUATIONS.\r
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document.write( "\n" );
document.write( "C) EVALUATE ALL THREE METHODS FOR EFFICIENCY AND EFFECTIVENESS.\"\r
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document.write( "V^2 - 3V - 54 = 0 (Please show me how the made that word problem into the equation? I know the answers are V = 9 or -6 \n" );
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Algebra.Com's Answer #639149 by Theo(13342)![]() ![]() You can put this solution on YOUR website! \r \n" ); document.write( "\n" ); document.write( "if your final equation is v^2 - 9v - 54 = 0, then the factors are (v-9) * (v+6).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the basic equation is rate * time = distance.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "distance equals 60 km. \n" ); document.write( "speed = r kmph \n" ); document.write( "time = t hours.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the basic equation becomes r * t = 60\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "when you are traveling 3 kmph slower, the rate becomes r-3.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "when it takes 3 hours and 20 minutes longer, the time becomes t + 3 and 1/3.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your rate * time equation becomes (r-3) * (t + 3 + 1/3) = 60.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the distance is the same. \n" ); document.write( "the rate is 3kmph slower. \n" ); document.write( "the time is 3 and 1/3 hours longer.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you have 2 equations that need to be solved simultaneously.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "they are r * t = 60 and (r-3) * (t + 3.33...) = 60\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "from r * t = 60, solve for t to get t = 60 / r.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "in (r-3) * (t + 3.33...) = 60, replace t with 60 / r to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(r-3) * (60/r + 3.33...) = 60\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "multiply both sides of the equation by r to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(r-3) * (60 + 3.33... * r) = 60 * r\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "multiply the factors to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "60r + 3.33... * r^2 - 180 - 10 * r = 60r\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the 60r on the left side of the equation and the 60 r on the right side of the equation cancel out and you get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3.33... * r^2 - 180 - 10 * r = 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "divide both sides of the equation by 3.33... (this is really 3 and 1/3), to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "r^2 - 54 - 3r = 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "re-arrange the terms in descending order of degree to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "r^2 - 3r - 54 = 0.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i used r for rate rather than v for velocity. \n" ); document.write( "it doesn't matter. \n" ); document.write( "the answer is the same.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "from r^2 - 3r - 54, you can factor the equation to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(r-9) * (r+6) = 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "that makes r = 9 or -6.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "r can't be negative, so r = 9.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "when r = 9, r * t = 60 becomes 9 * t = 60.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "solve for t to get t = 60/9 = 6 and 2/3.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "9 * (6 + 2/3) = 60 so that part checks out. \n" ); document.write( "your normal speed is 9 kmph and your normal time is 6 and 2/3 hours.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "when you cut your speed by 3 kmph, then your speed is 6 kmph. \n" ); document.write( "your time is increased by 3 and 1/3 hours.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "that makes you time equal to 6 and 2/3 + 3 and 1/3 = 10 hours.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "rate * time becomes 6 * 10 = 60 km.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "answer checks out and so is good.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i'm not quite sure what you were asked to solve here.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if it was just to factor the quadratic, then there are 3 basic methods you can choose.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "one is use of the quadratic formula.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "two is the box method.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "three is factor by grouping.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "four is the guess and check method.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i don't have time to show you how to do them, but here's some references.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "http://www.purplemath.com/modules/factquad.htm\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "http://www.purplemath.com/modules/factquad3.htm\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "http://www.regentsprep.org/regents/math/algtrig/atv1/revfactorgrouping.htm\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "http://www.regentsprep.org/regents/math/algtrig/atv1/revFactoring.htm\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "http://www.wtamu.edu/academic/anns/mps/math/mathlab/col_algebra/col_alg_tut17_quad.htm\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "as you can see, there's lots of methods.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "last one involves use of the quadratic formula.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "http://www.purplemath.com/modules/quadform.htm\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |