[zeshkani]

When you have a second oder reaction
 A + B --> C

and your are given both the initial concentration of A and B
and to find the half-life of both A and B would you just use this question t_1/2=1/k[A or B]_o
iam using this question but i just dont think its this simple,

is there something more to this equation, or i just used it the way it is

[Kryolith]

You are right. It is that simple 

2 A ----> B

[zeshkani]

but when we calculated the half life
of this ex:   
 A + 2B --->  P

we used this equation: t_1/2= 1/k*1/(B-2)(A)*Ln(A(B-2)(A/2))/(A-(A/2))(B)

so thats why iam still confused, and this one looks alot different then from the normal second order half life equation