X的三分之二次方等于九 求X的值
问题描述:
X的三分之二次方等于九 求X的值
答
x^(2/3)=9
[x^(1/3)]^2=3^2
x^(1/3)=3或x^(1/3)=-3
x=3^3或x=(-3)^3
x=27或x=-27