5.If `a.b =b .c=c.a=0` then the value of `[a,b,c]` is

If ab + bc + ca = 0, then find the value of (b)/((a+b)(b+c))+(c)/((a+c)(c+b))+(a)/((a+b)(c+a))

If a + b + c = 0 , then find the value of ( ( a + b ) / c + ( b + c )/a + ( c + a ) / b ) times ( a /( b + c ) + b /( c + a ) + c /( a + b ) ) is :

If a,b,c are in G.P. then the value of |(a,b,a+b),(b,c,b+c),(a+b,b+c,0)|= (A) 1 (B) -1 (C) a+b+c (D) 0

If a b+b c+c a=0 , then what is the value of (1/(a^2-b c)+1/(b^2-c a)+1/(c^2-a b)) ? (a) 0 (b) 1 (c) 3 (d) a+b+c