= (1/81) x (1/81x) x (1/81x) x (1/81x) x (81y) x (81y) x (81y) x a x = 1 x 1 x 1 x 1 x 81 x 81 x 81 x a x = 43046721a^2
= (1/81) x (1/81x) x (1/81x) x (1/81x) x (81y) x (81y) x (81y) x a x
= 1 x 1 x 1 x 1 x 81 x 81 x 81 x a x
= 43046721a^2