A^1/12*a^1/6)^4= a^(1/12+1/6)^4= a^3/12)^4=a^(3/12*4)=a
(-3)×(-3)+2×(-3)+4 1×(-3)×(-3) 9+(-6)+4 9 7 9 1 9 9
------------------------- × -------------------- = ------------- × ----- = --- × ----- = --- × --- = ----
1-(-3) (-3)×(-3)×(-3)-8 4 35 4 35 4 5 20