document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=828321>Question 828321</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The average age of 3 people is 15. If the 3rd person is 5 years older than the 1st person and the 2nd person is 4 years younger than the 1st person, what is the age of the 2nd person? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #499273 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=499273\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> ---<BR>\n" );
document.write( "(x + y + z)/3 = 15<BR>\n" );
document.write( "z = x + 5<BR>\n" );
document.write( "y = x - 4<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( "x + y + z = 45<BR>\n" );
document.write( "x - z = -5<BR>\n" );
document.write( "x - y = 4<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 = 14.666667 = 14 + 2/3<BR>\n" );
document.write( "y = 10.666667 = 10 + 2/3<BR>\n" );
document.write( "z = 19.666667 = 19 + 2/3<BR>\n" );
document.write( "---<BR>\n" );
document.write( "system matrix<BR>\n" );
document.write( "1 1 1<BR>\n" );
document.write( "1 0 -1<BR>\n" );
document.write( "1 -1 0<BR>\n" );
document.write( "---<BR>\n" );
document.write( "inverse of system matrix<BR>\n" );
document.write( "0.33333333 0.33333333 0.33333333<BR>\n" );
document.write( "0.33333333 0.33333333 -0.66666667<BR>\n" );
document.write( "0.33333333 -0.66666667 0.33333333<BR>\n" );
document.write( "---<BR>\n" );
document.write( "determinant of system matrix = -3<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<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );