We need to first find the intersection between Q and R, which is the common elements between both groups. We have:
[tex]Q\cap R=\mleft\lbrace r,e,x\mright\rbrace[/tex]
Now we need to determine the union between them:
[tex]P\cup(Q\cap R)=\mleft\lbrace e,x,a,c,t,r,e,x\mright\rbrace[/tex]
