document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=38203>Question 38203</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Solve the quadratic equation by factoring and applying the property \"ab=0 if and only if a=0 or b=0\"\r<BR>\n" );
document.write( "\n" );
document.write( "(x^2)-4x-21=0 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #23665 by </B><A HREF=/tutors/aboutme.mpl?userid=fractalier><B>fractalier(6550)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=fractalier><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=fractalier><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=23665\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> First we factor the trinomial<BR>\n" );
document.write( "x^2 - 4x - 21 = 0<BR>\n" );
document.write( "into its binomial factors:<BR>\n" );
document.write( "(x - 7)(x + 3) = 0<BR>\n" );
document.write( "Now if two quantities multiply together to make zero, one (or both) has to be zero...<BR>\n" );
document.write( "Thus x - 7 = 0 and x + 3 = 0 which leads to<BR>\n" );
document.write( "x = 7 or x = -3 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );