document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=852197>Question 852197</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find a1 and d for an arithmetic sequence with these terms: a4=9 and a7=18 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #513224 by </B><A HREF=/tutors/aboutme.mpl?userid=richwmiller><B>richwmiller(17219)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richwmiller><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=richwmiller><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=513224\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a4=9 and a7=18<BR>\n" );
document.write( "an = a1 + (n - 1)d<BR>\n" );
document.write( "9 = a1 + 3d,<BR>\n" );
document.write( "18 = a1 + 6d<BR>\n" );
document.write( "a1 = 0,   d = 3<BR>\n" );
document.write( " </SPAN>\n" );
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