document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=826365>Question 826365</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A plane set off to Portland at a speed of 298 miles per hour. On the return flight of 15 hours, the plane cruised at 234 miles per hour. How many hours long was the flight to Portland? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #498044 by </B><A HREF=/tutors/aboutme.mpl?userid=TimothyLamb><B>TimothyLamb(4379)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=TimothyLamb><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=TimothyLamb><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=498044\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> ---<BR>\n" );
document.write( "s = d/t<BR>\n" );
document.write( "d = s*t<BR>\n" );
document.write( "x = time outbound (to Portland)<BR>\n" );
document.write( "y = distance between cities<BR>\n" );
document.write( "---<BR>\n" );
document.write( "outbound:<BR>\n" );
document.write( "s = d/t<BR>\n" );
document.write( "y = 298x<BR>\n" );
document.write( "---<BR>\n" );
document.write( "inbound:<BR>\n" );
document.write( "s = d/t<BR>\n" );
document.write( "y = 234*15<BR>\n" );
document.write( "---<BR>\n" );
document.write( "linear system:<BR>\n" );
document.write( "---<BR>\n" );
document.write( "y = 298x<BR>\n" );
document.write( "y = 234*15<BR>\n" );
document.write( "---<BR>\n" );
document.write( "put the system of linear equations into standard form:<BR>\n" );
document.write( "---<BR>\n" );
document.write( "298x - y = 0<BR>\n" );
document.write( "y = 3510<BR>\n" );
document.write( "---<BR>\n" );
document.write( "copy and paste the above linear system in standard form into this matrix-method solver:<BR>\n" );
document.write( "https://sooeet.com/math/system-of-linear-equations-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "solution:<BR>\n" );
document.write( "x = time outbound (to Portland) = 11.778523 hours<BR>\n" );
document.write( "y = distance between cities = 3510 miles<BR>\n" );
document.write( "---<BR>\n" );
document.write( "system matrix<BR>\n" );
document.write( "298 -1<BR>\n" );
document.write( "0 1<BR>\n" );
document.write( "---<BR>\n" );
document.write( "inverse of system matrix<BR>\n" );
document.write( "0.0033557047 0.0033557047<BR>\n" );
document.write( "0 1<BR>\n" );
document.write( "---<BR>\n" );
document.write( "determinant of system matrix = 298<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve and graph linear equations:<BR>\n" );
document.write( "https://sooeet.com/math/linear-equation-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve quadratic equations, quadratic formula:<BR>\n" );
document.write( "https://sooeet.com/math/quadratic-formula-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve systems of linear equations up to 6-equations 6-variables:<BR>\n" );
document.write( "https://sooeet.com/math/system-of-linear-equations-solver.php </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );