3/4-5/10= in fractions and decimals format

Write the expression in complete factored form. 5n_(c - 3) - n(c - 3) =

What is the total area of the figure?

If set d is not the empty set but is a subset of set e, then which of the following is true? d ∩ e = d d ∩ e = e d ∩ e = ∅