document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=55441>Question 55441</A>: <I><SPAN STYLE=\"word-break: break-all;\"> To whom may it concern,\r<BR>\n" );
document.write( "\n" );
document.write( "I have this tricky question to solve.\r<BR>\n" );
document.write( "\n" );
document.write( "If x + 2y = -2 and x – 2y = 18, find the value of x^2 + 4y^2.\r<BR>\n" );
document.write( "\n" );
document.write( "According to my teacher, the answer is 164 but how ?\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Please help. Thanks.\r<BR>\n" );
document.write( "\n" );
document.write( "CH Lam </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #37632 by </B><A HREF=/tutors/aboutme.mpl?userid=tutorcecilia><B>tutorcecilia(2152)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=tutorcecilia><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=tutorcecilia><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=37632\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Remember that y=y and x=x, than<BR>\n" );
document.write( "Solve for y (or x) in each equation:<BR>\n" );
document.write( "x + 2y = -2 [solve for y]<BR>\n" );
document.write( "y=-1/2x-1<BR>\n" );
document.write( ".<BR>\n" );
document.write( "x – 2y = 18 [solve for y]<BR>\n" );
document.write( "y=1/2x-9<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Since y=y, than <BR>\n" );
document.write( "-1/2x-1=1/2x-9 [Solve for x]<BR>\n" );
document.write( "1x=8<BR>\n" );
document.write( "x=8<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Plugging (x=8) back into either of the original equations:<BR>\n" );
document.write( "x + 2y = -2<BR>\n" );
document.write( "(8)+2y=-2 [Solve for y]<BR>\n" );
document.write( "y=-10/2<BR>\n" );
document.write( "y=-5<BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Plug both values (x=8) and (y=-5) into the problem:<BR>\n" );
document.write( "x^2+4y^2<BR>\n" );
document.write( "(8)^2+4(-5)^2<BR>\n" );
document.write( "64+4(25)<BR>\n" );
document.write( "64+100<BR>\n" );
document.write( "164 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );