lg
3^x=10^-2
xlg3=-2
0.03^y=10^-2
ylg0.03=-2
所以1/x=-(lg3)/2
1/y=-(lg0.03)/2
1/x-1/y
=(lg0.03-lg3)/2
=[lg(0.03÷3)]/2
=[lg10^(-2)]/2
=-2/2
=-1