a^m=3, a^n=2,
a^(2m+3n)=a^(2m)*a^(3n)=[a^m]^2*[a^n]^3=3^2*2^3=9*8=72.
3^(x+1)*2^(x+1)=6^(x+1)=6^(2x-3),
x+1=2x-3, x=4.
(-1/2x^2)^3=(-1/2*16)^3=(-8)^3=-512
[-1/(2x^2)]^3=[-1/(2*16)]^3=-1/32768.
[(-1/2x)^2]^3=[(-1/8)^2]^3=[1/64]^3=1/262144