3. Repeat Exercise (1) when A=Z, and the relations are: (a) mRin|ml = 1721 (b) mR2 nm-ns1. (c) mR3 nm2 = 12(mod 7). (d) mR4nm-3) = |n-31. (e) mRgn m2 + nis even. (1) mRenom +3n = 0(mod 4). (g) mR71 mn>0. 4. Let E be the relation on the set of rational numbers Q defined by E-ad = bc. Prove that E is an equivalence relation, and bd 3 find а с 4. Let E be the relation on the set of rational numbers Q defined by E-o ad bc. Prove that E is an equivalence relation, and bed с find 4 Scanned with CamScanner