Given the rectangle that has length of ( 13x + 9 ) and a width of (7x + 4)
the perimeter of the rectangle = 2 * ( length + width )
So,
The perimeter = 2 * [ (13x + 9) + ( 7x + 4) ]
= 2 * ( 13x + 9 + 7x + 4)
= 2 * ( 20x + 13 )
= 2 * 20x + 2 * 13
= 40x + 26
So, the perimeter of the rectangle = 40x + 26