document.write( "Question 1030164: For the equation X2-13x=30, I got the answer (x-15)(X+2)by setting to zero so that: X squared -13x=30 becomes X squared -13x-30=0.
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document.write( "I found that -15 times 2 equals 30, and -15 plus 2 = -13. when I checked the answer, it said that X= -2 and X+15. Why isn't it 2 and -15?
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document.write( "Help, please?\r
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Algebra.Com's Answer #645063 by Cromlix(4381)![]() ![]() You can put this solution on YOUR website! Hi there, \n" ); document.write( "You are correct with your \n" ); document.write( "factorisation \n" ); document.write( "x^2 - 13x - 30 \n" ); document.write( "= (x - 15)(x + 2) \n" ); document.write( "To get the values for x \n" ); document.write( "you make x^2 - 13x - 30 = 0 \n" ); document.write( "(as you did) \n" ); document.write( "So, \n" ); document.write( "(x - 15)(x + 2)= 0 \n" ); document.write( "Take each separate bracket:- \n" ); document.write( "x - 15 = 0 \n" ); document.write( "x = 15 \n" ); document.write( "x + 2 = 0 \n" ); document.write( "x = -2 \n" ); document.write( "So values for x are:- \n" ); document.write( "x = -2, 15. \n" ); document.write( "Hope this helps :-) \n" ); document.write( " |