document.write( "Question 1207733: Solve the absolute value equation. \r
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document.write( "Solve |x + |3x-2|| = 2\r
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document.write( "Note: Here we have an absolute value inside another absolute value. \n" );
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Algebra.Com's Answer #845770 by math_tutor2020(3817)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "Answers: x = 0, x = 1\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Explanation\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Rule: If |x| = k then x = -k or x = k \n" ); document.write( "where k is nonnegative\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Using that rule we go from this \n" ); document.write( "|x + |3x-2|| = 2 \n" ); document.write( "to this \n" ); document.write( "x + |3x-2| = 2 or x + |3x-2| = -2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's solve each separately. \n" ); document.write( "x + |3x-2| = 2 \n" ); document.write( "|3x-2| = 2-x \n" ); document.write( "3x-2 = 2-x or 3x-2 = -(2-x) \n" ); document.write( "3x-2 = 2-x or 3x-2 = -2+x \n" ); document.write( "3x+x = 2+2 or 3x-x = -2+2 \n" ); document.write( "4x = 4 or 2x = 0 \n" ); document.write( "x = 4/4 or x = 0/2 \n" ); document.write( "x = 1 or x = 0 are two potential solutions.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now solve the other equation \n" ); document.write( "x + |3x-2| = -2 \n" ); document.write( "|3x-2| = -2-x \n" ); document.write( "3x-2 = -2-x or 3x-2 = -(-2-x) \n" ); document.write( "3x-2 = -2-x or 3x-2 = 2+x \n" ); document.write( "3x+x = -2+2 or 3x-x = 2+2 \n" ); document.write( "4x = 0 or 2x = 4 \n" ); document.write( "x = 0/4 or x = 4/2 \n" ); document.write( "x = 0 or x = 2 \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We have x = 0 show up again, but x = 2 is a new potential solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "----------------------------------\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Summary so far: \n" ); document.write( "The 3 potential solutions are \n" ); document.write( "x = 0, x = 1, or x = 2\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Like with any equation, we need to check said solutions. \n" ); document.write( "This step is very important. \n" ); document.write( "Let's start with x = 0. \n" ); document.write( "Replace each x with 0 and then apply PEMDAS. \n" ); document.write( "|x + |3x-2|| = 2 \n" ); document.write( "|0 + |3*0-2|| = 2 \n" ); document.write( "|0 + |0-2|| = 2 \n" ); document.write( "|0 + |-2|| = 2 \n" ); document.write( "|0 + 2| = 2 \n" ); document.write( "|2| = 2 \n" ); document.write( "2 = 2 \n" ); document.write( "That checks out. \n" ); document.write( "x = 0 is confirmed as a solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now let's try x = 1 \n" ); document.write( "|x + |3x-2|| = 2 \n" ); document.write( "|1 + |3*1-2|| = 2 \n" ); document.write( "|1 + |3-2|| = 2 \n" ); document.write( "|1 + |1|| = 2 \n" ); document.write( "|1 + 1| = 2 \n" ); document.write( "|2| = 2 \n" ); document.write( "2 = 2 \n" ); document.write( "That works as well. \n" ); document.write( "x = 1 is confirmed as a solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Lastly x = 2 \n" ); document.write( "|x + |3x-2|| = 2 \n" ); document.write( "|2 + |3*2-2|| = 2 \n" ); document.write( "|2 + |6-2|| = 2 \n" ); document.write( "|2 + |4|| = 2 \n" ); document.write( "|2 + 4| = 2 \n" ); document.write( "|6| = 2 \n" ); document.write( "6 = 2 \n" ); document.write( "The last statement is false since the numbers don't match up. \n" ); document.write( "A false equation at the end means the first equation of this sub-block is false when x = 2. \n" ); document.write( "It proves that x = 2 is NOT a solution. It's considered extraneous. \n" ); document.write( "You can see why we needed to check each potential solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "-------------------------------------------------------------------- \n" ); document.write( "--------------------------------------------------------------------\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Ultimately there are 2 solutions and they are x = 0, x = 1\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If we use Desmos to graph things out, then we get a V shape curve that represents y = |x + |3x-2|| \n" ); document.write( "https://www.desmos.com/calculator/aavxbn9myo \n" ); document.write( "I used the \"abs\" function to indicate absolute value in Desmos. \n" ); document.write( "Example: abs(3x-2) = |3x-2| \n" ); document.write( "The V shape and the horizontal line y = 2 intersect at the two points (0,2) and (1,2) shown in green and purple respectively. \n" ); document.write( "The x coordinates of these points are the solutions mentioned above. \n" ); document.write( " \n" ); document.write( " |