document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1138434>Question 1138434</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Each side of a square is increased 9 inches. When this happens, the area is multiplied by 16. How many inches in the side of the original square? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #756238 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=756238\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> each side of the square is increased by 9 inches.<BR>\n" );
document.write( "the area is multiplied by 16.\r<BR>\n" );
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document.write( "let x = the side of the square.<BR>\n" );
document.write( "the area of the square is therefore x^2.\r<BR>\n" );
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document.write( "when the side is increased by 9 inches, the area becomes (x+9)^2 = x^2 + 18x + 81.\r<BR>\n" );
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document.write( "you get x^2 + 18x + 81 = 16x^2\r<BR>\n" );
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document.write( "x^2 - 18x + 81 is the area when the side is increased by 9 inches.\r<BR>\n" );
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document.write( "16x^2 is the size of the new area which is 16 times the size of the original area.\r<BR>\n" );
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document.write( "subtract the left side of this equation from both sides of this equation to get:\r<BR>\n" );
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document.write( "16x^2 - x^2 = 18x - 81 = 0\r<BR>\n" );
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document.write( "combine like terms to get 15x^2 - 18x - 81 = 0\r<BR>\n" );
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document.write( "solve this quadratic equation by using the quadratic formula to get x = -1.8 or x = 3.\r<BR>\n" );
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document.write( "x has to be positive, so the solution has to be 3 or not at all.\r<BR>\n" );
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document.write( "when x = 3, x^2 = 9\r<BR>\n" );
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document.write( "when x = 3 + 9 = 12, x^2 = 144.\r<BR>\n" );
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document.write( "144 = 16 * 9, confirming the solution is correct.\r<BR>\n" );
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document.write( "your solution is that the original length of the size is 3 inches.\r<BR>\n" );
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