Let R be a commutative ring with 1. Let M₂ (R) be the 2 × 2 matrix ring over R and R[x] be the polyno- mial ring over R. Consider the subsets 0 s={[%]a,bER} S and J = {[86]la,bER} ber} 00 of M₂ (R), and consider the function : R[x] → M₂(R) given for any polynomial p(x) = co+c₁x+ ... + ₂x¹ € R[x] by CO C1 $ (p(x)) = [ 0 CO (1) Show that S is a commutative unital subring of M₂ (R).