document.write( "Question 598070: The point (5,y) is five units away from the point (2,70). What are the two possible values of y? \n" ); document.write( "
Algebra.Com's Answer #378507 by math-vortex(648)\"\" \"About 
You can put this solution on YOUR website!
Hi, there--
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\n" ); document.write( "Use the distance formula to find the distance between two points. The two different values of y will give you a point above and and a point below (2,70).
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\n" ); document.write( "The distance formula is
\n" ); document.write( "\"D=sqrt%28%28x%5B2%5D-x%5B1%5D%29%5E2%2B%28y%5B2%5D-y%5B1%5D%29%5E2%29\"
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\n" ); document.write( "Let (x[1],y[1])=(2,70).
\n" ); document.write( "Let (x[2],y[2])=(5,y).
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\n" ); document.write( "Substitute 5 for D and the known values for each point.
\n" ); document.write( "\"D=sqrt%28%28x%5B2%5D-x%5B1%5D%29%5E2%2B%28y%5B2%5D-y%5B1%5D%29%5E2%29\"
\n" ); document.write( "\"5=sqrt%28%285-2%29%5E2%2B%28y-70%29%5E2%29\"
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\n" ); document.write( "Simplify and solve for y.
\n" ); document.write( "\"5=sqrt%28%283%29%5E2%2B%28y-70%29%5E2%29\"
\n" ); document.write( "\"5=sqrt%289%2By%5E2-140y%2B4900%29\"
\n" ); document.write( "\"5=sqrt%28y%5E2-140y%2B4909%29\"
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\n" ); document.write( "Square both sides of the equation to clear the square root.
\n" ); document.write( "\"25=y%5E2-140y%2B4909\"
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\n" ); document.write( "Set the polynomial equal to zero, and factor.
\n" ); document.write( "\"y%5E2-140y%2B4884=0\"
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\n" ); document.write( "We can use the quadratic formula or the factoring method to solve. 4884 looks like a friendly number to I would try to factor it.
\n" ); document.write( " If I can't find factors right away, I switch to the quadratic formula. The Q.F. works for every quadratic, but not every quadratic is factorable.
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\n" ); document.write( "\"484=2%5E2%2A3%2A11%2A37\"; We want two factors with a sum of 140, and a product of 4884. I played around with the prime factors and got -2*3*11=-66 and -2*37=-74. So,
\n" ); document.write( "\"y-74=0\" OR \"y-66=0\"
\n" ); document.write( "\"y=74\" OR \"y=66\"
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\n" ); document.write( "Therefore, the two points are (5,66) and (5,74).
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\n" ); document.write( "Check your work for accuracy.
\n" ); document.write( "Distance between (2,70) and (5,66).
\n" ); document.write( "\"D=sqrt%28%285-2%29%5E2%2B%2866-70%29%5E2%29\"
\n" ); document.write( "\"D=sqrt%28%283%29%5E2%2B%28-4%29%5E2%29\"
\n" ); document.write( "\"D=sqrt%289%2B16%29\"
\n" ); document.write( "\"D=sqrt%2825%29\"
\n" ); document.write( "\"D=5\"
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\n" ); document.write( "\n" ); document.write( "Distance between(2,70) and (5,74).
\n" ); document.write( "\"D=sqrt%28%285-2%29%5E2%2B%2874-70%29%5E2%29\"
\n" ); document.write( "\"D=sqrt%28%283%29%5E2%2B%284%29%5E2%29\"
\n" ); document.write( "\"D=sqrt%289%2B16%29\"
\n" ); document.write( "\"D=sqrt%2825%29\"
\n" ); document.write( "\"D=5\"
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\n" ); document.write( "That's it! Feel free to email via gmail if you have questions about the solution
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\n" ); document.write( "Ms.Figgy
\n" ); document.write( "math.in.the.vortex@gmail.com
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