3^m=4
3^n=5
3^(2m+n)
=3^2m*3^n
=(3^m)^2*3^n
=4^2*5
=16*5
=80
3的2m+n次方
=3^2m*3^n (a^(m+n)=a^m*a^n)
=(3^m)²*3^n (a^(mn)=(a^m)^n)
=16*5
=80
不懂再问哦
3的2m+n
=3^2mx3^n
=(3^m)²x3^n
=4²x5
=80
3^m=4
3^n=5
3^(2m+n)=(3^m)^2 * (3^n)=16*5=80
3的2m次方=16,3的2m+n次方=90