An investment club invested part of $8000 at 10% annual interest the rest at 12%. if the annual income from these investments is $900, how much was invested at each rate

Let x be the amount invested  at 10%
so the amount invested at 12 % =  (8000-x)
   0.1x + 0.12(8000-x) = 900
   0.1x - 0.12x = 900- 960
   0.02x = 60
     x   =  3000      @ 10%
              8000 - 3000    =    5000     @ 12%