Question 1121944
x, length of side of original square


{{{(x+10)(x-2)=85}}}
You can use algebra if you want to --- quadratic equation.


Alternatively, note that the two factors differ by 12.  Can you find two factor whose difference is 12 and whose product is 85?  
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{{{system(x+10=17,and,x-2=5)}}}

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