document.write( "Question 84446: Please help...I need to write an equation in slope-intercept form using the following coordinates (-1,-7) and (-8,-2). I got as far as finding the slope m=-5/7 but I'm confused with rest of the equation. Thank you \n" ); document.write( "
Algebra.Com's Answer #60827 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
Use the form
\n" ); document.write( "\"m+=+%28y+-+y%5B1%5D%29+%2F+%28x+-+x%5B1%5D%29\"
\n" ); document.write( "and
\n" ); document.write( "\"m+=+%28y%5B2%5D+-+y%5B1%5D%29+%2F+%28x%5B2%5D+-+x%5B1%5D%29\"
\n" ); document.write( "where
\n" ); document.write( "\"P%5B1%5D\" = (x1 , y1)
\n" ); document.write( "\"P%5B2%5D\" = (x2 , y2)
\n" ); document.write( "(x1 , y1) = (-1 , -7)
\n" ); document.write( "(x2 , y2) = (-8 , -2)
\n" ); document.write( "\"m+=+%28-2+-+%28-7%29%29+%2F+%28-8+-+%28-1%29%29\"
\n" ); document.write( "\"m+=+%28-2+%2B+7%29+%2F+%28-8+%2B+1%29\"
\n" ); document.write( "\"m+=+-%285%2F7%29\"
\n" ); document.write( "now
\n" ); document.write( "\"m+=+%28y+-+y%5B1%5D%29+%2F+%28x+-+x%5B1%5D%29\"
\n" ); document.write( "\"-%285%2F7%29+=+%28y+-+%28-7%29%29+%2F+%28x+-+%28-1%29%29\"
\n" ); document.write( "\"-%285%2F7%29+=+%28y+%2B+7%29+%2F+%28x+%2B+1%29\"
\n" ); document.write( "multiply both sides by (x+1)
\n" ); document.write( "\"-%285%2F7%29%2A%28x+%2B+1%29+=+y+%2B+7\"
\n" ); document.write( "multiply both sides by 7
\n" ); document.write( "\"-5x+-+5+=+7y+%2B+49\"
\n" ); document.write( "\"7y+=+-5x+-+54\"
\n" ); document.write( "\"y+=+-%285%2F7%29x+-+54%2F7\"
\n" ); document.write( "check answer
\n" ); document.write( "Does line go through (-1 , -7) and (-8 , -2)?
\n" ); document.write( "\"y+=+-%285%2F7%29x+-+54%2F7\"
\n" ); document.write( "\"-7+=+-%285%2F7%29%2A%28-1%29+-+54%2F7\"
\n" ); document.write( "\"-7+=+5%2F7+-+54%2F7\"
\n" ); document.write( "\"-7+=+-%2849%2F7%29\"
\n" ); document.write( "\"-7+=+-7\" OK
\n" ); document.write( "--------------------
\n" ); document.write( "\"y+=+-%285%2F7%29x+-+54%2F7\"
\n" ); document.write( "\"-2+=+-%285%2F7%29%2A%28-8%29+-+54%2F7\"
\n" ); document.write( "\"-2+=+40%2F7+-+54%2F7\"
\n" ); document.write( "\"-2+=+-%2814%2F7%29\"
\n" ); document.write( "\"-2+=+-2\" OK
\n" ); document.write( "
\n" );