I'll just do 2 of them. U = {a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z} 1. (B ∩ C) ∩ A' Substitute ({a,f,g,h} ∩ {a,c,h,i}) ∩ {a,f,g}' We do this part first {a,f,g,h} ∩ {a,c,h,i}. Intersection means to take ONLY the elements in common, we get {a,h} to substitute for what's in the first parentheses and get: ({a,h}) ∩ {a,f,g}' Next we do {a,f,g}'. The ' means to take the complement, so we take all the elements in U except a,f,g which is {b,c,d,e,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z} So now we have: ({a,h}) ∩ {b,c,d,e,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z} Intersection means to take ONLY the elements in common, and there is only one element in common and that is h. answer: {h} ------------------------------------- 3. (A ∩ B) U (A ∩ C) ({a,b,c,d,e} ∩ {a,f,g,h}) U ({a,b,c,d,e} ∩ {a,c,h,i}) First we do ({a,b,c,d,e} ∩ {a,f,g,h}). Intersection means to take ONLY the elements in common, and and there is only one element in common and that is a. So we now have {a} U ({a,b,c,d,e} ∩ {a,c,h,i}) Next, we do ({a,b,c,d,e} ∩ {a,c,h,i}). Intersection means to take ONLY the elements in common, and and there is only two elements in common and they are a and c. So we substitute {a,c}, and have: {a} U {a,c} Union means to take ALL the elements in both sets whether in common or not. We list "a" only once, So the answer is: {a,c} Edwin