(x的m次方÷x2n)3÷x(m-n次档启方)答笑=x^[3(m-2n)-(m-n)]=x^(2m-5n)2m-5n=22m+5n=74m=9m=9/4n=1/24m^2-2n^2=81/4-1/2=79/4,求采行举如纳