document.write( "Question 151647This question is from textbook PreAlgebra
\n" ); document.write( ": I need to find z when z^6=64. I know the answer is 2 but what are the steps to solve for z? \n" ); document.write( "
Algebra.Com's Answer #111476 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
\"z%5E6=64\" Start with the given equation.\r
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\n" ); document.write( "\n" ); document.write( "\"z%5E6=2%5E6\" Rewrite 64 as \"2%5E6\".\r
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\n" ); document.write( "\n" ); document.write( "From here you can see that the answer is 2, but let's keep going\r
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\n" ); document.write( "\n" ); document.write( "\"root%286%2Cz%5E6%29=root%286%2C2%5E6%29\" Take the 6th root of both sides. This will eliminate the exponent \"6\"\r
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\n" ); document.write( "\n" ); document.write( "\"z=2\" Take the 6th root of \"z%5E6\" to get \"z\". Take the 6th root of \"2%5E6\" to get 2\r
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\n" ); document.write( "\n" ); document.write( "So the solution is \"z=2\"\r
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\n" ); document.write( "\n" ); document.write( "Here's another way to solve for \"z\"\r
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\n" ); document.write( "\n" ); document.write( "\"z%5E6=64\" Start with the given equation.\r
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\n" ); document.write( "\n" ); document.write( "\"z%5E6-64=0\" Subtract 64 from both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"z%5E6-2%5E6=0\" Rewrite 64 as \"2%5E6\".\r
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\n" ); document.write( "\n" ); document.write( "\"%28z%5E3%29%5E2-%282%5E3%29%5E2=0\". Rewrite \"z%5E6\" as \"%28z%5E3%29%5E2\". Rewrite \"2%5E6\" as \"%282%5E3%29%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "Now let \"A=z%5E3\" and \"B=2%5E3\"\r
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\n" ); document.write( "\n" ); document.write( "So we now have\r
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\n" ); document.write( "\n" ); document.write( "\"A%5E2-B%5E2=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28A%2BB%29%28A-B%29=0\" Factor using the difference of squares formula\r
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\n" ); document.write( "\n" ); document.write( "\"%28z%5E3%2B2%5E3%29%28z%5E3-2%5E3%29=0\" Plug in \"A=z%5E3\" and \"B=2%5E3\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28%28z%2B2%29%2A%28z%5E2-2%2Az%2B4%29%29%28z%5E3-2%5E3%29=0\" Factor the first binomial \"z%5E3%2B2%5E3\" using the sum of cubes formula\r
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\n" ); document.write( "\n" ); document.write( "\"%28%28z%2B2%29%2A%28z%5E2-2%2Az%2B4%29%29%28%28z-2%29%2A%28z%5E2%2B2%2Az%2B4%29%29=0\" Factor the second binomial \"z%5E3-2%5E3\" using the sum of cubes formula\r
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\n" ); document.write( "\n" ); document.write( "\"%28z%2B2%29%28z-2%29%28z%5E2-2%2Az%2B4%29%28z%5E2%2B2%2Az%2B4%29=0\" Rearrange the terms\r
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\n" ); document.write( "\n" ); document.write( "Now set each factor equal to zero:\r
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\n" ); document.write( "\n" ); document.write( "\"z%2B2=0\", \"z-2=0\", \"z%5E2-2%2Az%2B4=0\" or \"z%5E2%2B2%2Az%2B4=0\"\r
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\n" ); document.write( "\n" ); document.write( "So our first two solutions are \"z=-2\" or \"z=2\"\r
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\n" ); document.write( "\n" ); document.write( "Now let's solve \"z%5E2-2%2Az%2B4=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"z%5E2-2z%2B4=0\" Start with the given equation.\r
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\n" ); document.write( "\n" ); document.write( "Notice we have a quadratic equation in the form of \"az%5E2%2Bbz%2Bc\" where \"a=1\", \"b=-2\", and \"c=4\"\r
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\n" ); document.write( "\n" ); document.write( "Let's use the quadratic formula to solve for z\r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29\" Start with the quadratic formula\r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%28-%28-2%29+%2B-+sqrt%28+%28-2%29%5E2-4%281%29%284%29+%29%29%2F%282%281%29%29\" Plug in \"a=1\", \"b=-2\", and \"c=4\"\r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%282+%2B-+sqrt%28+%28-2%29%5E2-4%281%29%284%29+%29%29%2F%282%281%29%29\" Negate \"-2\" to get \"2\". \r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%282+%2B-+sqrt%28+4-4%281%29%284%29+%29%29%2F%282%281%29%29\" Square \"-2\" to get \"4\". \r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%282+%2B-+sqrt%28+4-16+%29%29%2F%282%281%29%29\" Multiply \"4%281%29%284%29\" to get \"16\"\r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%282+%2B-+sqrt%28+-12+%29%29%2F%282%281%29%29\" Subtract \"16\" from \"4\" to get \"-12\"\r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%282+%2B-+sqrt%28+-12+%29%29%2F%282%29\" Multiply \"2\" and \"1\" to get \"2\". \r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%282+%2B-+2i%2Asqrt%283%29%29%2F%282%29\" Simplify the square root (note: If you need help with simplifying square roots, check out this solver) \r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%282%29%2F%282%29+%2B-+%282i%2Asqrt%283%29%29%2F%282%29\" Break up the fraction. \r
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\n" ); document.write( "\n" ); document.write( "\"z+=+1+%2B-+sqrt%283%29%2Ai\" Reduce. \r
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\n" ); document.write( "\n" ); document.write( "\"z+=+1%2Bsqrt%283%29%2Ai\" or \"z+=+1-sqrt%283%29%2Ai\"Break up the expression. \r
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\n" ); document.write( "\n" ); document.write( "So the next two solutions are are \"z+=+1%2Bsqrt%283%29%2Ai\" or \"z+=+1-sqrt%283%29%2Ai\" \r
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\n" ); document.write( "\n" ); document.write( "which approximate to \"z=1%2B1.732%2Ai\" or \"z=1-1.732%2Ai\" \r
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\n" ); document.write( "\n" ); document.write( "Now let's solve \"z%5E2%2B2%2Az%2B4=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"z%5E2%2B2z%2B4=0\" Start with the given equation.\r
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\n" ); document.write( "\n" ); document.write( "Notice we have a quadratic equation in the form of \"az%5E2%2Bbz%2Bc\" where \"a=1\", \"b=2\", and \"c=4\"\r
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\n" ); document.write( "\n" ); document.write( "Let's use the quadratic formula to solve for z\r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29\" Start with the quadratic formula\r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%28-%282%29+%2B-+sqrt%28+%282%29%5E2-4%281%29%284%29+%29%29%2F%282%281%29%29\" Plug in \"a=1\", \"b=2\", and \"c=4\"\r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%28-2+%2B-+sqrt%28+4-4%281%29%284%29+%29%29%2F%282%281%29%29\" Square \"2\" to get \"4\". \r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%28-2+%2B-+sqrt%28+4-16+%29%29%2F%282%281%29%29\" Multiply \"4%281%29%284%29\" to get \"16\"\r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%28-2+%2B-+sqrt%28+-12+%29%29%2F%282%281%29%29\" Subtract \"16\" from \"4\" to get \"-12\"\r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%28-2+%2B-+sqrt%28+-12+%29%29%2F%282%29\" Multiply \"2\" and \"1\" to get \"2\". \r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%28-2+%2B-+2i%2Asqrt%283%29%29%2F%282%29\" Simplify the square root (note: If you need help with simplifying square roots, check out this solver) \r
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\n" ); document.write( "\n" ); document.write( "\"z+=+%28-2%29%2F%282%29+%2B-+%282i%2Asqrt%283%29%29%2F%282%29\" Break up the fraction. \r
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\n" ); document.write( "\n" ); document.write( "\"z+=+-1+%2B-+sqrt%283%29%2Ai\" Reduce. \r
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\n" ); document.write( "\n" ); document.write( "\"z+=+-1%2Bsqrt%283%29%2Ai\" or \"z+=+-1-sqrt%283%29%2Ai\" Break up the expression. \r
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\n" ); document.write( "\n" ); document.write( "So the next two solutions are \"z+=+-1%2Bsqrt%283%29%2Ai\" or \"z+=+-1-sqrt%283%29%2Ai\" \r
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\n" ); document.write( "\n" ); document.write( "which approximate to \"z=-1%2B1.732%2Ai\" or \"z=-1-1.732%2Ai\" \r
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\n" ); document.write( "\n" ); document.write( "Answer:\r
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\n" ); document.write( "\n" ); document.write( "So altogether, we have the 6 solutions\r
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\n" ); document.write( "\n" ); document.write( "\"z=-2\", \"z=2\", \"z+=+1%2Bsqrt%283%29%2Ai\" , \"z+=+1-sqrt%283%29%2Ai\", \"z+=+-1%2Bsqrt%283%29%2Ai\" or \"z+=+-1-sqrt%283%29%2Ai\"
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