How to do these questions?

(b)
依同等級 (加減為一個等級, 乘除又是一個等級)
計算, 四則運算(加減乘除)是採由左而右的原則,
先計算
  (-d)^3 ÷ (-6d^3)^2 = (-d^3) ÷ (36d^6) = -1/(36d^3)
再將結果除以 9d^4:
 [ -1/(36d^3) ] ÷ (9d^4) = -1/(36d^3) × 1/(9d^4)
    = -1/(324d^7) = (-1/324)d^(-7)

(c)
(2x^5y^3)^4 ÷ [ (6x^3y^2)^4/(-3xy^2)^3 ]
    = (16x^20y^12) ÷ [(1296x^12y^8)/(-27x^3y^6)]
    = 16x^20y^12 ÷ (-48)x^9y^2
    = [16/(-48)]x^11y^1o
    = (-1/3)x^11y^1o

(d)
(3^(2n) × 27^n)^3
    = 3^(2n×3) × (3^3)^(n×3)
    = 3^(6n) × 3^(9n)
    = 3^(15n)
或者
  (3^(2n) × 27^n)^3
      = [3^(2n) × (3^3)^n]^3
      = [3^(2n) × 3^(3n)]^3
      = (3^(5n))^3
      = 3^(15n)