Whats three fractions the matches 4out of 12

How to do this , and can some one explain

Given the expression (7 ? 4i) ? (2 + 6i), perform the indicated operation and write the answer in the form a + bi.

Consider a= {x|x is alive} f={x|x is in france} m={x|x is a national monument} w{x|x is a woman}. which statements are true regarding elements of the given sets? check all that apply.