Question 766953
The frame starts with its inner border of 12 inch by 9 inch, and extends 1 w on each side for some number w.  The entire outer dimension for the frame is {{{12+2w}}} and {{{9+2w}}}.  



The area covered with the whole frame  outer dimensions is {{{(12+2w)(9+2w)}}}.  The part of this area which is NOT the frame, is the area of the picture, {{{12*9}}} {{{inch^2}}}.


{Total area} - {picture area} = {frame area}


READ; THINK; UNDERSTAND. 
SOLVE. The rest of this is left for you.


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