若m,n为正整数,且x^2m=3,x^n=5,求2x^4m-2n的值
问题描述:
若m,n为正整数,且x^2m=3,x^n=5,求2x^4m-2n的值
答
2x^4m-2n
=2×(x^2m)²÷(x^n)²
=2×3²÷5²
=18/25