The average person living in argentina

Solve the system. -a+4b+2c=-8 3a+b-4c=9 b=-1 a.(0,11) ,-1,2) c.(1,1,-2) d.(2,-1,-1)

Can someone me and do the problem plz so i can understand it more better

Ateacher noticed 5/8 of the students were wearing either blue shorts or white shorts. write two different ways this could be done.