document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=536075>Question 536075</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Which values of b will make the expression x^2 + bx+400 a perfect square trinomial?<BR>\n" );
document.write( "a. -80,80 b.-40,40 c.-100,100 d.-20,20 <BR>\n" );
document.write( "my wrong choice was d. which is the answer...? thx! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #352118 by </B><A HREF=/tutors/aboutme.mpl?userid=april4869><B>april4869(19)</B></A><img src=\"/images/stars/stars-06.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=april4869><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=april4869><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=352118\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> x^2 + bx + 400 will be a perfect square if b = 40. That is since 400 = 20^2, then b must be 2*20.\r<BR>\n" );
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document.write( "This follows the standard form (x + a)^2 = x^2 + 2ax + a^2 \r<BR>\n" );
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document.write( "So the answer is 40.. and you can insert 40 into the equation to check. Rule of thumb, if you are unsure about multiple choice questions like this..just plug in each answer to see which one works! Sometimes it's the easiest way:) </SPAN>\n" );
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