已知x^m=3,x^n=1/3,求x^2m-3n的值

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已知x^m=3,x^n=1/3,求x^2m-3n的值
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已知x^m=3,x^n=1/3,求x^2m-3n的值
已知x^m=3,x^n=1/3,求x^2m-3n的值

已知x^m=3,x^n=1/3,求x^2m-3n的值
(x^m)^2=x^2m=3^2=9
(x^n)^3=x^3n=(1/3)^3=1/27
x^2m-3n
=(x^m)^2÷(x^n)^3
=9÷1/27
=243

x^m=3,x^n=1/3
可以推出 x=3 m=1 n=-1
x^2m-3n
=3^2+3
=12

9/(1/27)=243

x^2m-3n=(x^m)^2/(x^n)^3=9*27