document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1191489>Question 1191489</A>: <I><SPAN STYLE=\"word-break: break-all;\"> z varies jointly with x and y. When x=5 and y=2, z=70. Find z when x=4 and y =8.\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #823263 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=823263\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> joint variation formula is z = k * x * y<BR>\n" );
document.write( "when x = 5 and y = 2 and z = 70, formula becomes:<BR>\n" );
document.write( "70 = k * 5 * 2<BR>\n" );
document.write( "simplify to get:<BR>\n" );
document.write( "70 = 10 * k<BR>\n" );
document.write( "solve for k to get:<BR>\n" );
document.write( "k = 7.<BR>\n" );
document.write( "when x = 4 and y = 8 and k = 7, the formula becomes:<BR>\n" );
document.write( "z = 7 * 4 * 8<BR>\n" );
document.write( "solve for z to get z = 224<BR>\n" );
document.write( "that's your solution.<BR>\n" );
document.write( "k is the constant of variation.<BR>\n" );
document.write( "it remains the same when the other variables in the equation change.<BR>\n" );
document.write( "solve for k first, then use k to solve for another of the variables, such as z, in this case.\r<BR>\n" );
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