6. A rectangular garden measuring \( 42 ft \) by \( 20 ft \) is to be surrounded by a paved border of uniform width \( x \) . a) Draw and label a diagram of the garden. b) Write a simplified expression for the area of the garden and border. c) The total area of the garden and border is \( 1248 ft ^ { 2 } \) . Find the width \( ( x ) \) of the border.