Answer:
= -10d^4 + 12d^2s + 25d^2 - 30s
The problem is:

We now do L.C.M. of numerator and add, also do L.C.M. of denominator and add together:

Dividing by a fraction is same as multiplying by its reciprocal, so we have:

x cancels out, so can multiply and write:

This is the simplified form.
ANSWER: 
First box, third box, fifth and also sixth =D
Step-by-step Answer:
Since there are no repetitions in the five letters of the word ZEBRA, the number of permutations is 5! = 120 = 5*4*3*2*1.