document.write( "Question 1177575: The quadratic equation x² + kx + 36=0 has\r
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document.write( "two different real roots. Find the set of possible values of k. \n" );
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Algebra.Com's Answer #806637 by greenestamps(13198)![]() ![]() You can put this solution on YOUR website! \n" ); document.write( " \n" ); document.write( "The product of a and b has to be 36. \n" ); document.write( "Choose any two numbers a and b whose product is 36; the sum (a+b) will be one of the possible values for k. \n" ); document.write( "One example: a=9, b=4; ab=36; a+b=13. One possible value of k is 13. \n" ); document.write( "One more: a=-3, b=-12; ab=36; a+b=-15. Another possible value of k is -15. \n" ); document.write( "Note the statement of the problem is not complete; with no restriction on the values of a and b, there are an infinite number of possible values of k. For example... \n" ); document.write( "a=8, b=4.5; ab=36; a+b=12.5; another possible value of k is 12.5. \n" ); document.write( "From that example, you can see that you could choose ANY value for a; then b would be 36/a, and you would get another value for a+b. \n" ); document.write( "So undoubtedly the question was supposed to ask for the set of possible INTEGER values of k. \n" ); document.write( "I'll let you finish the problem; you should find 18 different possible integer values for k. \n" ); document.write( "Note that two of those 18 values of k will be 12 and -12, where the a and b are both 6 or both -6. Since the problem says the roots are different, you should find 16 different integer values of k in which the two roots are different. \n" ); document.write( " \n" ); document.write( " |