document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=328113>Question 328113</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A small rectangular playground that is 10ft by 14ft is going to have a grass border of a uniform width on all sides. If the area of the grass border is 145 sqare feet, how wide is the border? \r<BR>\n" );
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document.write( "I have tried to think of the correct formula but have come up blank! please can someone help me with this one!  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #235022 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=235022\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A small rectangular playground that is 10ft by 14ft is going to have a grass<BR>\n" );
document.write( " border of a uniform width on all sides.<BR>\n" );
document.write( " If the area of the grass border is 145 square feet, how wide is the border? <BR>\n" );
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document.write( "Find the area of the playground: 10 * 14 = 140 sq/ft<BR>\n" );
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document.write( "Let x = the width of the border<BR>\n" );
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document.write( "Then the overall dimensions including the border will be: (2x+10) by (2x+14)<BR>\n" );
document.write( "Find the overall area (A)<BR>\n" );
document.write( "A = (2x+10)*(2x+14)<BR>\n" );
document.write( "FOIL<BR>\n" );
document.write( "A = 4x^2 + 28x + 20x + 140<BR>\n" );
document.write( "A = 4x^2 + 48x + 140<BR>\n" );
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document.write( "Overall area - playground area = border area, therefore:<BR>\n" );
document.write( "4x^2 + 48x + 140 - 140 = 145<BR>\n" );
document.write( "Arrange as a quadratic equation<BR>\n" );
document.write( "4x^2 + 48x - 145 = 0<BR>\n" );
document.write( "You can use the quadratic formula here, but this will factor<BR>\n" );
document.write( "(2x-5)(2x+29) = 0<BR>\n" );
document.write( "The positive solution is what we want here<BR>\n" );
document.write( "2x = 5<BR>\n" );
document.write( "x = 5/2<BR>\n" );
document.write( "x = 2.5 ft is the width of the grass border<BR>\n" );
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document.write( "Check our solution by finding the overall area and subtracting the playground area<BR>\n" );
document.write( "(5+10)*(5+14) = 285 sq/ft<BR>\n" );
document.write( "285 - 140 = 145 sq/ft; confirms our solution of x=2.5  </SPAN>\n" );
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