document.write( "Question 886150: What is answer to (x-5)^(2/3)=9 With 2/3 being a fractional exponent. \n" ); document.write( "
Algebra.Com's Answer #535737 by Theo(13342)\"\" \"About 
You can put this solution on YOUR website!
BIG difference.
\n" ); document.write( "x = -22 and 32 are your solutions.
\n" ); document.write( "here's why:\r
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\n" ); document.write( "\n" ); document.write( "(x-5)^(2/3)= 9 is the original equation.\r
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\n" ); document.write( "\n" ); document.write( "(x-5)^(2/3) is the same as ((x-5)^2)^(1/3)\r
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\n" ); document.write( "\n" ); document.write( "your equation becomes:\r
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\n" ); document.write( "\n" ); document.write( "((x-5)^2)^(1/3) = 9\r
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\n" ); document.write( "\n" ); document.write( "you want to get rid of the cube root, so you cube both sides of the equation.\r
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\n" ); document.write( "\n" ); document.write( "you get:\r
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\n" ); document.write( "\n" ); document.write( "(((x-5)^2)^(1/3))^3 = 9^3\r
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\n" ); document.write( "\n" ); document.write( "simplify this and you get:\r
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\n" ); document.write( "\n" ); document.write( "(x-5)^2 = 9^3 which becomes (x-5)^2 = 729\r
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\n" ); document.write( "\n" ); document.write( "simplify (x-5)^2 by expanding it and you get:\r
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\n" ); document.write( "\n" ); document.write( "x^2 - 10x + 25 = 729\r
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\n" ); document.write( "\n" ); document.write( "subtract 25 from both sides of the equation to get:\r
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\n" ); document.write( "\n" ); document.write( "x^2 - 10x - 704 = 0\r
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\n" ); document.write( "\n" ); document.write( "factor this to get:\r
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\n" ); document.write( "\n" ); document.write( "(x+22) * (x-32) = 0\r
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\n" ); document.write( "\n" ); document.write( "solve for x to get the possible solutions of:
\n" ); document.write( "x = -22 or x = 32\r
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\n" ); document.write( "\n" ); document.write( "confirm your solutions are good by replacing x in the oridinal equations to see if the equations hold true.
\n" ); document.write( "this step is necessary since there are problems where the possible solutions are not feasible.\r
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\n" ); document.write( "\n" ); document.write( "the original equation is:\r
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\n" ); document.write( "\n" ); document.write( "(x-5)^(2/3)= 9\r
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\n" ); document.write( "\n" ); document.write( "replace x with -22 and you get:\r
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\n" ); document.write( "\n" ); document.write( "(-22-5)^(2/3) = 9 which becomes (-27)^(2/3) = 9\r
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\n" ); document.write( "(-27)^(2/3) is equivalent to either:\r
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\n" ); document.write( "\n" ); document.write( "(-27)^2 = 729 and the cube root of 729 is eqjual to 3.
\n" ); document.write( "alternatively:
\n" ); document.write( "cube root of (-27) = (-3) and (-3)^2 = 9\r
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\n" ); document.write( "\n" ); document.write( "replace x with 32 and you get:\r
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\n" ); document.write( "\n" ); document.write( "((32-5)^(2/3) = 9 which becomes ((27)^(2/3) = 9\r
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\n" ); document.write( "\n" ); document.write( "27 squared = 729 and the cube root of 729 is equal to 9
\n" ); document.write( "alternatively:
\n" ); document.write( "cube root of 27 = 3 and 3 squared = 9.\r
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\n" ); document.write( "\n" ); document.write( "looks like both solutions are good.\r
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\n" ); document.write( "\n" ); document.write( "i graphed the equation of y = (x-5)^(2/3) and the equation of y = 9 to confirm graphically that this is true.
\n" ); document.write( "in the graph, you can see the intersection points of the 2 equations are at x = -22 and x = 32.
\n" ); document.write( "that confirms the solution is correct graphically.\r
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\n" ); document.write( "\n" ); document.write( "the graph is shown below:\r
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