tolong no. 4 pleasee

a. a-b={a,b,c,d}
b. b-a={g, h, j}
c. {a, b, c, d} n {a, b, c, d, e, f}
{a, b, c,d}
d.{a,b,c,d} u {g,h, j} ={a, b, c, d, g,h,j}