document.write( "Question 700725: write an equation in standard form using only integers for each of line described
\n" ); document.write( "the line through (-2,a) and (a,3) has slope -1/2 \n" ); document.write( "
Algebra.Com's Answer #431988 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
\r\n" );
document.write( "We'll need the slope formula first\r\n" );
document.write( "\r\n" );
document.write( "m = \"%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29\"\r\n" );
document.write( "\r\n" );
document.write( "And then we will need point-slope formula:\r\n" );
document.write( "\r\n" );
document.write( "y - y1 = m(x - x1)\r\n" );
document.write( "\r\n" );
document.write( "(-2,a) and (a,3) has slope -1/2\r\n" );
document.write( "\r\n" );
document.write( "m = \"%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29\"\r\n" );
document.write( "\r\n" );
document.write( "m = \"%28%283%29-%28a%29%29%2F%28%28a%29-%28-2%29%29\"\r\n" );
document.write( "\r\n" );
document.write( "m = \"%283-a%29%2F%28a%2B2%29\"\r\n" );
document.write( "\r\n" );
document.write( "We are give that that equals \"-1%2F2\"\r\n" );
document.write( "\r\n" );
document.write( "\"%283-a%29%2F%28a%2B2%29\" = \"-1%2F2\"\r\n" );
document.write( "\r\n" );
document.write( "\"%283-a%29%2F%28a%2B2%29\" = \"%28-1%29%2F2\"\r\n" );
document.write( "\r\n" );
document.write( "Cross multiply:\r\n" );
document.write( "\r\n" );
document.write( "2(3-a) = -1(a+2)\r\n" );
document.write( "\r\n" );
document.write( "  6-2a = -a-2\r\n" );
document.write( "    -a = -8\r\n" );
document.write( "     a = 8\r\n" );
document.write( "\r\n" );
document.write( "So the points \r\n" );
document.write( "\r\n" );
document.write( "(-2,a) and (a,3) become the points\r\n" );
document.write( "\r\n" );
document.write( "(-2,8) and (8,3) \r\n" );
document.write( "\r\n" );
document.write( "Using the point-slope form:\r\n" );
document.write( "\r\n" );
document.write( "  y - y1 = m(x - x1)\r\n" );
document.write( "\r\n" );
document.write( "(-2,8)\r\n" );
document.write( "\r\n" );
document.write( "   y - 8 = \"-1%2F2%29\"(x - (-2) )\r\n" );
document.write( "\r\n" );
document.write( "   y - 8 = \"-1%2F2%29\"(x + 2)\r\n" );
document.write( "\r\n" );
document.write( "Multiply both sides by 2\r\n" );
document.write( "\r\n" );
document.write( "2(y - 8) = 2×\"-1%2F2%29\"(x + 2)\r\n" );
document.write( "\r\n" );
document.write( " 2y - 16 = -1(x + 2)\r\n" );
document.write( "\r\n" );
document.write( " 2y - 16 = -x - 2\r\n" );
document.write( "\r\n" );
document.write( "  x + 2y = 14\r\n" );
document.write( "\r\n" );
document.write( "Edwin
\n" ); document.write( "
\n" );