Make denomenators the same
times left denomenator by (x+3)/(x+3) and right one by (x-9)/(x-9)

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if expandded we get
So, 30 is the perimeter. We are told the table is twice as long as it is wide.
So, we have think of 2 numbers, one being twice as big than the other. So, it is a rectangle The two number represents the length and the width. To find the perimeter we add all the lengths and the widths. Since the pool table is a rectangle we have two lengths and two widths.
So,
the tow numbers be 10 and 5. 5 is half of 10 and, when multiplied by 2 it is 10. So just to make sure the numbers 5 and 10 work out lets do a calculation.
So,
10+5+10+5 = 30feet. This proves that the sides are these two numbers.
Total length of the board = 30 inch
Length of,
-- First piece = x
-- Second piece = 4x
-- Third piece = 5x
5x + 4x + x = 30
10x = 30
x = 3
Therefore, the lengths of:
-- First piece = 3 inch
-- Second piece = 4*3 = 12 inch
-- Third piece = 5*3 = 15 inch