document.write( "Question 1105031: For part of the first year of a dog's life, its growth can be approximated using a linear function.Emilie has two puppies: a Border collie and a younger Saint Bernard.During a 4-week period, the Border collie grows from 13.4 kg to 17 while the Saint Bernard grows from 6 kg to 12.4 kg.Suppose each dog grows at a constant rate.Will the dogs ever have the same mass?If so, approximately what is the mass? \n" ); document.write( "
Algebra.Com's Answer #719779 by josmiceli(19441)\"\" \"About 
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The collie's weight is a straight line over the 4 wks
\n" ); document.write( "You are given 2 points on that line
\n" ); document.write( "The St. Bernard's weight is a straight line over the 4 wks
\n" ); document.write( "You are given 2 points on that line
\n" ); document.write( "---------------------------------------------------
\n" ); document.write( "Call the start of the 4 wk period \"+t+=+0+\"
\n" ); document.write( "Let \"+m+\" = mass in kg
\n" ); document.write( "The 2 points for the collie:
\n" ); document.write( "( 0, 13.4 )
\n" ); document.write( "( 4, 17 )
\n" ); document.write( "The 2 points for the St. Bernard:
\n" ); document.write( "( 0, 6 )
\n" ); document.write( "( 4, 12.4 )
\n" ); document.write( "-------------------------------
\n" ); document.write( "Use the general point-slope formula:
\n" ); document.write( "For collie:
\n" ); document.write( "\"+%28+m+-+13.4+%29+%2F+%28+t+-+0+%29+=+%28+17+-+13.4+%29+%2F+%28+4+-+0+%29+\"
\n" ); document.write( "\"+%28+m+-+13.4+%29+%2F+t+=+3.6+%2F+4+\"
\n" ); document.write( "\"+%28+m+-+13.4+%29+%2F+t+=+.9+\"
\n" ); document.write( "\"+m+-+13.4+=+.9t+\"
\n" ); document.write( "\"+m+=+.9t+%2B+13.4+\"
\n" ); document.write( "-----------------------
\n" ); document.write( "For St. Bernard:
\n" ); document.write( "\"+%28+m+-+6+%29+%2F+%28+t+-+0+%29+=+%28+12.4+-+6+%29+%2F+%28+4+-+0+%29+\"
\n" ); document.write( "\"+%28+m+-+6+%29+%2F+t+=+6.4+%2F+4+\"
\n" ); document.write( "\"+%28+m+-+6+%29+%2F+t+=+1.6+\"
\n" ); document.write( "\"+m+-+6+=+1.6t+\"
\n" ); document.write( "\"+m+=+1.6t+%2B+6+\"
\n" ); document.write( "-----------------------
\n" ); document.write( "find the intersection of the lines:
\n" ); document.write( "Set the masses equal to eachother
\n" ); document.write( "\"+.9t+%2B+13.4+=+1.6t+%2B+6+\"
\n" ); document.write( "\"+.7t+=+7.4+\"
\n" ); document.write( "\"+t+=+10.57+\"
\n" ); document.write( "and
\n" ); document.write( "\"+m+=+1.6t+%2B+6+\"
\n" ); document.write( "\"+m+=+1.6%2A10.57+%2B+6+\"
\n" ); document.write( "\"+m+=+16.91+%2B+6+\"
\n" ); document.write( "\"+m+=+22.91+\" kg
\n" ); document.write( "Their masses will both be 22.91 kg in 10.57 weeks
\n" ); document.write( "Check the math\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
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