document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1071259>Question 1071259</A>: <I><SPAN STYLE=\"word-break: break-all;\"> What is the equation for an exponential function that passes through the points (1,2) and (3,8)? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #686199 by </B><A HREF=/tutors/aboutme.mpl?userid=htmentor><B>htmentor(1343)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=htmentor><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=htmentor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=686199\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The general form of an exponential function is f(x) = y = c*a^x<BR>\n" );
document.write( "We can determine the values of the constants a and c by using the two given points.<BR>\n" );
document.write( "From (1,2) we get 2 = ca^1 = ca -> c = 2/a -> y = (2/a)*a^x<BR>\n" );
document.write( "From (3,8) we get 8 = (2/a)*a^3 -> a = 2; therefore c = 1<BR>\n" );
document.write( "So the function is y = 2^x\r<BR>\n" );
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