document.write( "Question 97624: HELP HELP HELP HELP ME PLEASE!!!!!\r
\n" ); document.write( "\n" ); document.write( "\"+sqrt%28+x-8+%29+\" = x-10
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Algebra.Com's Answer #71041 by bucky(2189)\"\" \"About 
You can put this solution on YOUR website!
Given:
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\n" ); document.write( "\"sqrt%28x+-+8%29+=+x+-+10\"
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\n" ); document.write( "Get rid of the radical on the left side by squaring both sides of the equation. On the left
\n" ); document.write( "side after squaring you just have x - 8 and on the right side you square the quantity (x - 10).
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\n" ); document.write( "After squaring is completed the equation is:
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\n" ); document.write( "\"x+-+8+=+x%5E2+-+20x+%2B+100\"
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\n" ); document.write( "Let's get the equation in a more conventional form by merely switching (or transposing)
\n" ); document.write( "sides ... swapping the left and right sides to get:
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\n" ); document.write( "\"x%5E2+-+20x+%2B+100+=+x+-+8\"
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\n" ); document.write( "Get rid of the x on the right side by subtracting x from both sides. The result is:
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\n" ); document.write( "\"x%5E2+-+21x+%2B+100+=+-8\"
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\n" ); document.write( "Now get rid of the -8 on the right side by adding 8 to both sides. When you do that the
\n" ); document.write( "equation reduces to:
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\n" ); document.write( "\"x%5E2+-+21x+%2B+108+=+0\"
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\n" ); document.write( "This is quadratic equation in a conventional form. If you play with it a little, you will
\n" ); document.write( "find that it factors to become:
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\n" ); document.write( "\"%28x-12%29%28x+-+9%29+=+0\"
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\n" ); document.write( "The left side of this equation will be zero (the same as the right side) if either of the
\n" ); document.write( "factors is equal to zero.
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\n" ); document.write( "So possible answers come from setting each of the factors equal to zero to get:
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\n" ); document.write( "\"x+-+12+=+0\"
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\n" ); document.write( "which is solved by adding 12 to both sides to get:
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\n" ); document.write( "\"x+=+12\"
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\n" ); document.write( "and another solution is obtained from setting:
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\n" ); document.write( "\"x+-+9+=+0\"
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\n" ); document.write( "which can be solved by adding 9 to both sides to get:
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\n" ); document.write( "\"x+=+9\"
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\n" ); document.write( "So we have two possible answers ... x = 12 and x = 9.
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\n" ); document.write( "Check both answers by returning to the equation that you were given and substitute
\n" ); document.write( "(one at a time) +12 for x and + 9 for x to see if they both work.
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\n" ); document.write( "If you substitute +12 for x in the equation you were given you get:
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\n" ); document.write( "\"sqrt%2812-8%29+=+12+-+10\"
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\n" ); document.write( "which reduces to:
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\n" ); document.write( "\"sqrt%284%29+=+12+-10\"
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\n" ); document.write( "and this furthermore reduces to:
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\n" ); document.write( "\"2+=+2\"
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\n" ); document.write( "So this answer checks.
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\n" ); document.write( "Now try letting x = 9. Substitute 9 for x in the given equation and you get:
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\n" ); document.write( "\"sqrt%289-8%29+=+9+-+10\"
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\n" ); document.write( "This simplifies to:
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\n" ); document.write( "\"sqrt%281%29+=+-1\"
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\n" ); document.write( "but the square root of 1 is +1 and this does not equal -1. So the answer x = 9 does not
\n" ); document.write( "work out in the equation. Discard this answer. The only answer that satisfies the original
\n" ); document.write( "equation is x = 12.
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\n" ); document.write( "Hope this helps you to understand the problem a little better.
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