Question 945845
First find set A U B


This is just the set of A and B combined and any duplicates are tossed


A U B = {q, s, u, w, y} U {q, s, y, z} = {q, s, u, w, y, z}


So A U B = {q, s, u, w, y, z}


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Now look at set U = {q, r, s, t, u, v, w, x, y, z}


Use a red pen or something to mark all of the letters that are in set U that are also in set <font color=red>A U B = {q, s, u, w, y, z}</font>


U = {<font color="red">q</font>, r, <font color="red">s</font>, t, <font color="red">u</font>, v, <font color="red">w</font>, x, <font color="red">y</font>, <font color="red">z</font>}


They will scratched out and erased


{<s><font size=5 color="red">q</font></s>, r, <s><font size=5 color="red">s</font></s>, t, <s><font size=5 color="red">u</font></s>, v, <s><font size=5 color="red">w</font></s>, x, <s><font size=5 color="red">y</font></s>, <s><font size=5 color="red">z</font></s>}


Leaving this behind


{r, t, v, x} 


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Therefore,


(A U B)' = {r, t, v, x}