Question 1103578
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..., by removing a strip of equal width from <b>the east and the north sides</b>.
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{{{(65-x)(35-x)=1000}}}

Notice that the two factors for 1000 differ by 30.  You might try to use that.  


Otherwise,  {{{65*35-35x-65x+x^2=1000}}}
{{{x^2-100x+65*35-1000=0}}}
{{{x^2-100x+1275=0}}}
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discriminant {{{10000-4*1275=4900=70^2}}}

{{{x=(100+- 70)/2}}}

{{{highlight(x=15,or,cross(x=85))}}}


New dimensions:  50 meters by 20 meters