document.write( "Question 210015: what number must be added to the numerator of 3/10 to produce the fraction 4/5 \n" ); document.write( "
Algebra.Com's Answer #158721 by rapaljer(4671)\"\" \"About 
You can put this solution on YOUR website!
Let x = the number to be added.\r
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\n" ); document.write( "\n" ); document.write( "\"+%283%2Bx%29%2F10+=+4%2F5\"\r
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\n" ); document.write( "\n" ); document.write( "Remember that if \"a%2Fb=+c%2Fd\" then \"ad=bc\"\r
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\n" ); document.write( "\n" ); document.write( "So, \"+%283%2Bx%29%2F10+=+4%2F5\" means that \"5%283%2Bx%29=+4%2A10\"\r
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\n" ); document.write( "\n" ); document.write( "15+5x = 40
\n" ); document.write( "5x=40-15
\n" ); document.write( "5x=25
\n" ); document.write( "x=5\r
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\n" ); document.write( "\n" ); document.write( "Check: Add 5 to the numerator of 3 which gives you 8. \"8%2F10=+4%2F5\".\r
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\n" ); document.write( "\n" ); document.write( "It checks!!!\r
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\n" ); document.write( "\n" ); document.write( "R^2
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