A rectangular garden has its length 1m greater than twice its breadth. When each dimension is decreased by 3m, the area reduces to 84m2.
(i) Taking the breadth of the garden to be xm, set up a quadratic equation in x that models the given information.
(ii) Factorise the quadratic equation obtained in part (i) and find all possible values of x.
(iii) Hence determine the original dimensions of the garden.