[（-3ab）²×a³+2a³×（-3ab）³×1/2b]÷（3a²b²）² ,其中a=1/3,b=-

[（-3ab）²×a³+2a³×（-3ab）³×1/2b]÷（3a²b²）²
=[-3a^5b^2-3a^6b^2]÷9a^4b^4
=-a/3b^2-a^2/3b^2
=-a/3b^2*(a-1)
=-a/3b^2*0
=0好像不对[（-3ab）²×a³+2a³×（-3ab）³×1/2b]÷（3a²b²）² =[-3a^5b^2-27a^6b^2]÷9a^4b^4=-a/3b^2-3a^2/b^2=-a/3b^2*(a-9)b等于什么？b=负二分之一[（-3ab）²×a³+2a³×（-3ab）³×1/2b]÷（3a²b²）² =[9a^5b^2-27a^6b^2]÷9a^4b^4=a/b^2-3a^2/b^2=a/b^2*(1-3a)=1/(-1/2)^2*(1-3)=1/(1/4)*(-2)=4*(-2)=-8