3 and 1/2=3 and 2/4
3 and 2/4-9 and 3/4=3-9+2/4-3/4=-6-1/4=-6 and 1/4
now
divide by -2 and 1/2
negative divided by negative is positive
also
dividingn fractions, invert secondn one and multiply them
(a/b)/(c/d)=(a/b)(d/c)=(ad)/(bc)
so
convert to improper
6 and 1/4=6+1/4=24/4+1/4=25/4
2 and 1/2=2+1/2=4/2+1/2=5/2
(25/4)/(5/2)=(25/4)(2/5)=50/20=5/2=2.5
answer is D