document.write( "Question 1097145: Hello, i have problem on a word problem for linear equation. hope you can help me\r
\n" ); document.write( "\n" ); document.write( "When making a telephone call using a calling card, a call lasting 5 minutes costs$1.45. A call lasting 15 minutes costs $3.45. Let y be the cost of making a call lasting x minutes using a calling card. Write a linear equation that models the cost of making a call lasting x minutes. \n" ); document.write( "

Algebra.Com's Answer #711548 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Actually, you are given 2 points on a line, and
\n" ); document.write( "since 2 points dfine a line, you can plot the line.
\n" ); document.write( "The points are:
\n" ); document.write( "( 5, 1.45 )
\n" ); document.write( "( 15, 3.45 )
\n" ); document.write( "Use the general point-slope formula
\n" ); document.write( " $\"+%28+y+-+1.45+%29+%2F+%28+x+-+5+%29+=+%28+3.45+-+1.45+%29+%2F+%28+15+-+5+%29+\"$
\n" ); document.write( " $\"+%28+y+-+1.45+%29+%2F+%28+x+-+5+%29+=+2+%2F+10+\"$
\n" ); document.write( " $\"+%28+y+-+1.45+%29+%2F+%28+x+-+5+%29+=+1+%2F+5+\"$
\n" ); document.write( "Multiply both sides by $\"+5%2A%28+x+-+5+%29+\"$
\n" ); document.write( " $\"+5%2A%28+y+-+1.45+%29+=+x+-+5+\"$
\n" ); document.write( " $\"+5y+-+7.25+=+x+-+5+\"$
\n" ); document.write( " $\"+5y+=+x+%2B+2.25+\"$
\n" ); document.write( " $\"+y+=+%281%2F5%29%2Ax+%2B+.45+\"$
\n" ); document.write( " $\"+y+=+.2x+%2B+.45+\"$
\n" ); document.write( "-------------------------------
\n" ); document.write( "check:
\n" ); document.write( "does it go through ( 5, 1.45 ) ?
\n" ); document.write( " $\"+1.45+=+.2%2A5+%2B+.45+\"$
\n" ); document.write( " $\"+1.45+=+1.45+\"$
\n" ); document.write( "OK
\n" ); document.write( "check ( 15, 3.45 )
\n" ); document.write( " $\"+3.45+=+.2%2A15+%2B+.45+\"$
\n" ); document.write( " $\"+3.45+=+3.45+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );