Question 475209
A U B = set of the combination of sets A and B


A ∩ B = set of common elements between sets A and B




a)


Since B = {4, 5, 8, 9}, and C = {6, 8, 10}



This means that 


B ∩ C = {8} 



because 8 is the only thing sets B and C have in common


So 

A U (B ∩ C)



becomes



A U {8}


which tells us to simply add the element 8 to set A to get the final answer of 


{4, 5, 6, 7, 8}



So A U (B ∩ C) = {4, 5, 6, 7, 8}



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