SOLUTION: A photograph is 10 inches long and 8 inches wide. It is surrounded by a border of uniform width. If the border and photo together occupy and area of 168 square inches, how wid

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Question 638924: A photograph is 10 inches long and 8 inches wide. It is surrounded by a border of uniform width. If the border and photo together occupy and area of 168 square inches, how wide is the border?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
If +x+ is the width of the border,
the border adds +2x+
to the length and width, so
+%28+10%2B+2x+%29%2A%28+8+%2B+2x+%29+=+168+
+80+%2B+16x+%2B+20x+%2B+4x%5E2+=+168+
+4x%5E2+%2B+36x+-+88+=+0+
+x%5E2+%2B+9x+-+22+=+0+
+%28+x+%2B+11+%29%2A%28+x+-+2+%29+=+0+
+x+=+2+ ( ignore the negative root )
The border is 2 inches wide
check:
+%28+10%2B+2x+%29%2A%28+8+%2B+2x+%29+=+168+
+%28+10%2B+2%2A2+%29%2A%28+8+%2B+2%2A2+%29+=+168+
+14%2A12+=+168+
+168+=+168+