2x-y+z=6 -----------------(1)
x-3y-2z=13--------------(2)
2x-3y-3z=16------------(3)
a) 3*(1) - (2); [ multiply (1) with 3 subtract (2) from it ]
you get, 7x + 5z = 5 -----------------(4)
b) (3) - (2); { subtract (2 ) from (3) }
you get; x - z = 3 ---------------------(5)
c) (4) + 5* (5);
you get, 12x = 20
x = 20 / 12
x = 5 / 3