Question 1207922
<pre>
A ∩ (B ∪ C)<sup>c</sup>

Substitute the sets for the capital letters:

{q, s, u, w, y} ∩ ({q, s, y, z} ∪ {v, w, x, y, z})<sup>c</sup>

Do in the parentheses first which is a "∪", which means "union", so we 
combine the two sets on each side of the "∪" into one (we don't repeat 
the y or z, which are elements of both):

{q, s, u, w, y} ∩ ({q, s, y, z, v, w, x})<sup>c</sup>

Now we do the "<sup>c</sup>", which means "complement", by replacing it with 
all the elements of U, the universal set, that are not in 
{q, s, y, z, v, w, x}

So when we remove all those from U, the universal set, we have this left
{r, t, u} so that's the complement set.  So now we have

{q, s, u, w, y} ∩ {r, t, u}

Now we do the "∩", which means "intersection", so we take only the 
elements that are common to both sets, and ignore all the others. So the final
answer is {u}, which has only one element, and is called a "singleton".

Answer: {u}

Edwin</pre>