No 3 yang tau tolong chat

a.p={-10,-9,-8,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10}
q={-8,-7,-6,-5,-4,-3,-2,-1,0,1,2}
r={-2,-1,0,1,2,3,4,5,6,7,8}
s={-5,-4,-3,-2,-1,0,1,2,3,4,5}
b.p U q={-10,-9,-8,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10}
p U r={-10,-9,-8,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10}
q U r={-8,-7,-6,-5,-4,-3,-2,-1,9,1,2,3,4,5,6,7,8}
p U q U r={-10,-9,-8,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10}
c.