已知x^m=2,x^n=3(m,n是正整数).求:(1)x^2m+3n;(2)x^2m+x^3n

问题描述:

已知x^m=2,x^n=3(m,n是正整数).求:(1)x^2m+3n;(2)x^2m+x^3n

(1)
x^(2m+3n)
=x^(2m)*x^(3n)
=(x^m)^2*(x^n)^3
=2^2*3^3
=4*27
=108
(2)
x^2m+x^3n
=x^(2m)+x^(3n)
=(x^m)^2+(x^n)^3
=2^2+3^3
=4+27
=31