12-foot by 15-foot patio is increased by placing a stone border around the patio. The width of the border is the same all around the patio. The perimeter of the patio after it is expanded is 74 feet. A rectangle has a length of 15 feet and height of 12 feet. The equation which represents x, the width of the border is 2 left-bracket (12 + 2 x) + (15 + 2 x) right-bracket = 74. What is the width of the border?