document.write( "Question 922400: For what value(s) of k will the lines
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document.write( "kx+5y=2 and 2x+(k+3)y=4 be:\r
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document.write( "a) parallel to each other? b)perpendicular to each other \n" );
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Algebra.Com's Answer #559561 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! For what value(s) of k will the lines \n" ); document.write( "kx+5y=2 and 2x+(k+3)y=4 be: a) parallel to each other? \n" ); document.write( ": \n" ); document.write( "put both equations in the slope intercept form \n" ); document.write( "kx + 5y = 2 \n" ); document.write( "5y = -kx + 2 \n" ); document.write( "y = \n" ); document.write( "and \n" ); document.write( "2x + (k+3)y = 4 \n" ); document.write( "(k+3)y = -2x + 4 \n" ); document.write( "y = \n" ); document.write( "the slope of parallel lines are equal; therefore\ \n" ); document.write( " \n" ); document.write( "cross multiply \n" ); document.write( "-k(k+3) = 5 * -2 \n" ); document.write( "-k(k+3) = -10 \n" ); document.write( "multiply both sides by -1 \n" ); document.write( "k(k+3) = 10 \n" ); document.write( "k^2 + 3k - 10 = 0 \n" ); document.write( "factors to \n" ); document.write( "(k+5)(k-2) = 0 \n" ); document.write( "the positive solution \n" ); document.write( "k = 2 \n" ); document.write( "the negative solution will also work \n" ); document.write( "k = -5 \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "b)perpendicular to each other \n" ); document.write( "the relationship of slopes of perpendicular lines: m1 * m2 = -1, therefore \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "2k = -1(5k+15) \n" ); document.write( "2k = -5k - 15 \n" ); document.write( "2k + 5k = -15 \n" ); document.write( "7k = -15 \n" ); document.write( "k = \n" ); document.write( " \n" ); document.write( " |