document.write( "Question 1018075: Given that u^2 is directly proportional to cube of w.find the value of w when u=27,if u=8 when u=8. \n" ); document.write( "
Algebra.Com's Answer #634261 by Theo(13342)\"\" \"About 
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the general formula for direct variation is y = kx\r
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\n" ); document.write( "\n" ); document.write( "when y = u^2 and x = w^3, this formula becomes u^2 = k * w^3\r
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\n" ); document.write( "\n" ); document.write( "when u = 8 and w = 8,m this formula becomes 8^2 = k * 8^3.\r
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\n" ); document.write( "\n" ); document.write( "solve for k to get k = 8^2 / 8^3 = 1/8.\r
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\n" ); document.write( "\n" ); document.write( "when u = 27 and k = 1/8, the formula becomes 27^2 = 1/8 * w^3\r
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\n" ); document.write( "\n" ); document.write( "multiply both sides of this equation by 8 to get 27^2 * 8 = w^3\r
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\n" ); document.write( "\n" ); document.write( "take the cube root of each side of this equation to get cube root of (27^2 * 8) = cube root of (w^3).\r
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\n" ); document.write( "\n" ); document.write( "simplify to get cube root of (27^2 * 8) = w.\r
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\n" ); document.write( "\n" ); document.write( "this can be expressed as cube root of (27 * 27 * 8)\r
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\n" ); document.write( "\n" ); document.write( "since cube root of 27 is 3 and cube root of 8 is 2, this becomes:\r
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\n" ); document.write( "\n" ); document.write( "cube root of (3^3 * 3^3 * 2^3) which can then be expressed as cube root of (3^3) * cube root of (3^3) * cube root of (2^3) which can then be expressed as 3 * 3 * 2 which is equal to 18.\r
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\n" ); document.write( "\n" ); document.write( "the cube root of (27^2 * 8) is equal to 18.\r
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\n" ); document.write( "\n" ); document.write( "you can use your calculator to confirm.\r
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\n" ); document.write( "\n" ); document.write( "when u = 27, w is equal to 18.\r
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\n" ); document.write( "\n" ); document.write( "you get u^2 = k * w^3 becomes 27^2 = 1/8 * 18^3 which becomes 729 = 5832 / 8 which becomes 729 = 729.\r
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\n" ); document.write( "\n" ); document.write( "this ocnfirms the solution is good.\r
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