A = B + C

Add the BE (A) back to A , BE(B) back to B and BE (C) back to C

you will end up with nucleons which are all the same on both sides. The equation looks like this :

oooooo =oooooo

A + BE(A) = B + BE(B) + C+ BE(C)

A = B + C + Energy released [ BE (B + C - A)]

This in general is true if reaction occurs , energy is released.

If A is reactant and B and C are products.

The energy released is in the form of KE of product and gamma photon. However if the KE of the reactant is not zero , than KE of product - KE of reactant and gamma photon is the equal to energy released.

However if BE(A) is greater than BE (B+C) , the equation is written :

BE(A) - BE (B+C) = Energy required for reaction to occur. This energy is in the form of KE of the reactant which must be larger than the product.