In the reaction A2(g)  +  4B2(g) ⇌  2AB4(g),  ∆H <0. The decomposition of AB4(g) will be favoured at

A2(g)+4B2(g) ⇌  2AB4(g), ∆H <0(=-ve)2AB4(g)⇌A2(g)+4B2(g) ; ∆H=+ve     As decomposition of AB4 is endothermic, so reaction proceeds with increase in temperature. Secondly forward reaction proceeds with increase in number of moles of products, so low pressure favours it.