問數，指數定律

[2^x * 4^(x + 2)] / [2^(x + 3) * 16^2x]
= [2^x * (2^2)^(x + 2)] / [2^(x + 3) * (2^4)^2x]
= [2^x * 2^(2x + 4)] / [2^(x + 3) * 2^8x]
= 2^(x + 2x + 4) / 2^(x + 3 + 8x)
= 2^(3x + 4) / 2^(9x + 3)
= 2^(3x + 4 - 9x - 3)
= 2^(1 - 6x)
[3^x * 9^(x + 4)] / [27^x * 3^(x - 4)]
= [3^x * (3^2)^(x + 4)] / [(3^3)^x * 3^(x - 4)]
= [3^x * 3^(2x + 8)] / [3^3x * 3^(x - 4)]
= [3^(x + 2x + 8)] / [3^(3x + x - 4)]
= 3^(3x + 8) / 3^(4x - 4)
= 3^(3x + 8 - 4x + 4)
= 3^(12 - x)

2^x 同 16^2x 是否分別在同一個分子分母 ? 定係分開咁乘?