Solve for 3c+4u=33 and 6c+3u=36

6c+3u=36

6c+3u-6c=36-6c

3u=36-6c

3u/3=36-6c/3

u=12-2c

3c+4u=33

3c+4(12-2c)=33

3c+(4)(12) (4)(-2c)=33

3c+48-8c=33

48-5c=33

48-5c-48=33-48

-5c=-15

-5c/-5=-15/-5

c=3

u=12-2c

u=12-2(3)

u=12-6=6