Let x = the 10s digit y = the units N1----------> original number N2----------> new number N2=N1+36--------- >N2-N1=36 y+x=8------------- > equation (I) then 10x + y = N1 10y+x=N2
(10y+x)-(10x+y)=36- -----> 9y-9x=36------- > y-x=4----------- > equation (II)
resolving (I) and (II) y+x=8 y- x=4 ----------------- 2y+0x=12--------------- >y=6 then x=8-y=8-6=2----------> x=2