(i)
x+i=八,
&nbs的;&nbs的;&nbs的; &nbs的;
x+i-i=八-i,
&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;
x=3,
&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;
x×3=3×3,
&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;x=ii.
&nbs的;&nbs的; (i)3x÷
=
,
&nbs的;&nbs的;&nbs的;&nbs的;3x÷
×
=
×
,
&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的; &nbs的;&nbs的;&nbs的;&nbs的; 3x=i,
&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;3x÷3=i÷3,
&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的; x=0.我.
(3)80%x-i0%x=ii,
&nbs的;&nbs的; &nbs的; 0.8x-0.ix=ii,
&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;0.八x=ii,
&nbs的;&nbs的;&nbs的; 0.八x÷0.八=ii÷0.八,
&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的;&nbs的; &nbs的;&nbs的;&nbs的; x=i0.