Question

If a, b, c are non-zero real numbers and if the system of equations 

(a - 1) x = y + z

(b - 1) y = z + x

(c - 1) z = x + y

has a non-trivial solution, then ab + bc + ca equals

(A) a + b + c

(B) abc

(C) 1

(D) -1

Answer 1

Answer is (B) abc

For the non-trivial solution