For SN2 pathway we use an strong nucleophile (OH-,CN-) so they can easily substitute X(halogen) group from rear side.
While for elimination bimolecular reactions we use a strong conjugated base (RCH2O- or alc.kOH) so that it takes proton from carbon near by to halogen,thus forming an alkene .
While in my text book I had found
I was agree with first diagram stating that bulky group will more tend to show elimination rather that substitution but in second diagram they show ethoxide ion giving substitution reaction .
To which I disagree, According to me it be should also show elimination reaction.