document.write( "Question 1192806: Solve the inequalities for the range of x if any.
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document.write( "|x|+|2-x|<2 \n" );
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Algebra.Com's Answer #824725 by greenestamps(13203)![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "The other tutor uses a method that I would not choose; there are two other standard solution methods that I think are easier. \n" ); document.write( "And his final statement that the inequality is a contradiction is not mathematically correct; his statement should be that the solution set to the inequality is the empty set. \n" ); document.write( "First alternative method.... \n" ); document.write( "|x-a| can be interpreted as the distance between x and a. So \n" ); document.write( "|x| = |x-0| \n" ); document.write( "|2-x| = |x-2| \n" ); document.write( "Then the inequality can be read as \"the sum of the distances from x to 0 and from x to 2 is less than 2\". Picturing points on a number line, it is easy to see that |x|+|2-x| is EQUAL to 2 for 0 < x < 2; and |x|+|2-x| is greater than 2 everywhere else. So there is no solution the inequality; its solution is the empty set. \n" ); document.write( "Second alternative method.... \n" ); document.write( "The terms |x| and |2-x| mean the behavior of the expression changes at x=0 and x=2. So analyze the three cases for x less than 0, for x between 0 and 2, and for x greater than 2. \n" ); document.write( "(1) If x is less than 0, then |x| = -x and |2-x| = 2-x. The inequality is then \n" ); document.write( "(-x)+(2-x)<2 \n" ); document.write( "-2x+2<2 \n" ); document.write( "-2x<0 \n" ); document.write( "x>0 \n" ); document.write( "But that \"solution\" is not in the range of x values we are working with (x less than 0). So there is no solution for x less than 0. \n" ); document.write( "(2) If x is between 0 and 2, then |x| = x and |2-x| = 2-x; the inequality is then \n" ); document.write( "(x)+(2-x)<2 \n" ); document.write( "2<2 \n" ); document.write( "That statement is never true; so there is no solution for x between 0 and 2. \n" ); document.write( "(3) If x is greater than 2, then |x| = x and |2-x| = x-2; the inequality is then \n" ); document.write( "(x)+(x-2)<2 \n" ); document.write( "2x-2<2 \n" ); document.write( "2x<4 \n" ); document.write( "x<2 \n" ); document.write( "But that \"solution\" is again not in the range of x values we are working with (x greater than 2). So there is no solution for x greater than 2. \n" ); document.write( "This shows that there is no solution to the inequality in any of the three intervals; therefore, there is no solution to the inequality -- the solution is the empty set. \n" ); document.write( " \n" ); document.write( " |