document.write( "Question 87338: Please help. I need to find three consectutive integers such that the sum of their squares is 77. Thanks!! \n" ); document.write( "
Algebra.Com's Answer #63259 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Let x=1st #, y=2nd #, z=3rd #\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2By%5E2%2Bz%5E2=77\" This is the translation of \"the sum of their (each number) squares is 77\"\r
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\n" ); document.write( "\n" ); document.write( "Since each number is consecutive, we're really adding 1 each time. So \r
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\n" ); document.write( "\n" ); document.write( "\"y=x%2B1\" and \"z=%28x%2B1%29%2B1=x%2B2\"\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2B%28x%2B1%29%5E2%2B%28x%2B2%29%5E2=77\" Plug in \"y=x%2B1\" and \"z=x%2B2\"\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2B%28x%5E2%2B2x%2B1%29%2B%28x%5E2%2B4x%2B4%29=77\" Foil\r
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\n" ); document.write( "\n" ); document.write( "\"3x%5E2%2B6x%2B5=77\" Combine like terms\r
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\n" ); document.write( "\n" ); document.write( "\"3x%5E2%2B6x%2B5-77=0\" Subtract 77 from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"3x%5E2%2B6x-72=0\" Combine like terms\r
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\n" ); document.write( "\n" ); document.write( "Now lets use the quadratic formula to solve for x\r
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\n" ); document.write( "\n" ); document.write( "Starting with the general quadratic\r
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\n" ); document.write( "\n" ); document.write( "\"ax%5E2%2Bbx%2Bc=0\"\r
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\n" ); document.write( "\n" ); document.write( "the general form of the quadratic equation is:\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29\"\r
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\n" ); document.write( "\n" ); document.write( "So lets solve \"3%2Ax%5E2%2B6%2Ax-72=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-6+%2B-+sqrt%28+%286%29%5E2-4%2A3%2A-72+%29%29%2F%282%2A3%29\" Plug in a=3, b=6, and c=-72\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-6+%2B-+sqrt%28+36-4%2A3%2A-72+%29%29%2F%282%2A3%29\" Square 6 to get 36\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-6+%2B-+sqrt%28+36%2B864+%29%29%2F%282%2A3%29\" Multiply \"-4%2A-72%2A3\" to get \"864\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-6+%2B-+sqrt%28+900+%29%29%2F%282%2A3%29\" Combine like terms in the radicand (everything under the square root)\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-6+%2B-+30%29%2F%282%2A3%29\" Simplify the square root\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-6+%2B-+30%29%2F6\" Multiply 2 and 3 to get 6\r
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\n" ); document.write( "\n" ); document.write( "So now the expression breaks down into two parts\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-6+%2B+30%29%2F6\" or \"x+=+%28-6+-+30%29%2F6\"\r
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\n" ); document.write( "\n" ); document.write( "Lets look at the first part:\r
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\n" ); document.write( "\n" ); document.write( "\"x=24%2F6\" Add the terms in the numerator\r
\n" ); document.write( "\n" ); document.write( "\"x=4\" Divide\r
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\n" ); document.write( "\n" ); document.write( "So one answer is\r
\n" ); document.write( "\n" ); document.write( "\"x=4\"\r
\n" ); document.write( "\n" ); document.write( "Now lets look at the second part:\r
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\n" ); document.write( "\n" ); document.write( "\"x=-36%2F6\" Subtract the terms in the numerator\r
\n" ); document.write( "\n" ); document.write( "\"x=-6\" Divide\r
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\n" ); document.write( "\n" ); document.write( "So another answer is\r
\n" ); document.write( "\n" ); document.write( "\"x=-6\"\r
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\n" ); document.write( "\n" ); document.write( "So our solutions are:\r
\n" ); document.write( "\n" ); document.write( "\"x=4\" or \"x=-6\"\r
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\n" ); document.write( "\n" ); document.write( "Notice when we graph \"3%2Ax%5E2%2B6%2Ax-72\" we get:\r
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\n" ); document.write( "\n" ); document.write( "\"+graph%28+500%2C+500%2C+-16%2C+14%2C+-16%2C+14%2C3%2Ax%5E2%2B6%2Ax%2B-72%29+\"\r
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\n" ); document.write( "\n" ); document.write( "and we can see that the roots are \"x=4\" and \"x=-6\". This verifies our answer\r
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\n" ); document.write( "\n" ); document.write( "So our first number could be 4 or -6\r
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\n" ); document.write( "\n" ); document.write( "Lets use \"x=4\" to find the 2nd and 3rd number\r
\n" ); document.write( "\n" ); document.write( "\"y=4%2B1\" and \"z=4%2B2\"
\n" ); document.write( "\"y=5\" and \"z=6\"\r
\n" ); document.write( "\n" ); document.write( "So we have 3 numbers: 4,5,6\r
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\n" ); document.write( "\n" ); document.write( "Check:
\n" ); document.write( "\"4%5E2%2B5%5E2%2B6%5E2=77\"
\n" ); document.write( "\"16%2B25%2B36=77\"
\n" ); document.write( "\"77=77\" works\r
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\n" ); document.write( "\n" ); document.write( "So the 3 numbers 4,5,6 work\r
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\n" ); document.write( "\n" ); document.write( "Now lets use \"x=-6\" to find the 2nd and 3rd number\r
\n" ); document.write( "\n" ); document.write( "\"y=-6%2B1\" and \"z=-6%2B2\"
\n" ); document.write( "\"y=-5\" and \"z=-4\"\r
\n" ); document.write( "\n" ); document.write( "So we have 3 numbers: -6,-5,-4\r
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\n" ); document.write( "\n" ); document.write( "Check:
\n" ); document.write( "\"%28-6%29%5E2%2B%28-5%29%5E2%2B%28-4%29%5E2=77\"
\n" ); document.write( "\"36%2B25%2B16=77\"
\n" ); document.write( "\"77=77\" works\r
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\n" ); document.write( "\n" ); document.write( "So the 3 numbers -6,-5,-4 work\r
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\n" ); document.write( "\n" ); document.write( "Answer:\r
\n" ); document.write( "\n" ); document.write( "So if you allow negative numbers, you get 2 possible answers\r
\n" ); document.write( "\n" ); document.write( "4,5,6\r
\n" ); document.write( "\n" ); document.write( "or \r
\n" ); document.write( "\n" ); document.write( "-6,-5,-4\r
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