For the elementary process below, the activation energy is 31 kJ mol−1 and the enthalpy of reaction is 12 kJ mol−1. What is Ea for the reverse process, in kJ mol−1 ?

Question

For the elementary process below, the activation energy is 31 kJ mol−1 and the enthalpy of reaction is 12 kJ mol−1. What is Ea for the reverse process, in kJ mol−1 ?
A + B ⇌ AB

DrBob222 · Accepted Answer

I answered this question for Layla earlier today. Here is the link.
https://www.jiskha.com/questions/1817043/for-the-elementary-process-below-the-activation-energy-is-31-kj-mol-1-and-the-enthalpy
I didn't give an equation for that but
Eareverse = Eafwd - dHfwd.
Eareverse = 31 - (12) = ?