2x+5y-3z=4应是2x+5y+3z=4吧,
4^x*32^y^8^z-(1/2)^-4
=2^(2x+5y+3z)-16
=2^4-16=0没错，是2x+5y-3z=4若是2x+5y-3z=4，原式=2^(2x+5y+3z)-16=2^(4+6z)-16，无法求值.