若x的3M次方=4,Y的3n次方=5,求(x的2m次方)的立方+(y的n次方)的立方-x的2m次方×y的n次方×x的4m次方×Y的n次方
问题描述：
若x的3M次方=4,Y的3n次方=5,求(x的2m次方)的立方+(y的n次方)的立方-x的2m次方×y
的n次方×x的4m次方×Y的n次方
答
=x^6m+y^4n-x^2m*y^n*x^4m*y^n
=x^2(3m)+y^n*y^3n-x^6m*y^2n
=4^2+5*y^n-4^2+y^2n
=4^2-(5*y^3n)
=4^2-5^2
=-9
答
x的3M次方=4,y的3n次方=5,＝＝＞,y的n次方=5^(1/3)
(x的2m次方)的立方+(y的n次方)的立方-x的2m次方×y的n次方×x的4m次方×Y的n次方
=x的6M次方+y的3n次方﹣x的6M次方×y的2n次方
=16+5﹣16×5^(2/3)
=21﹣46.78
=﹣25.78