The length of a rectangular garden is 6 m less than twice its breadth. If the area of the garden is 135 m² and the breadth is taken as x metres, which of the following quadratic equations can be used to find x?
a) x2−6x−135=0
b) 2x2−6x+135=0
c) 2x2−6x−135=0
d) 2x2+6x−135=0