Perform the following operations and prove closure. 1. (x)/(x+3) + (x+2)/(x+5)

2. (x+4)/(x^2+5x+6) * (x+3)/(x^2-16)

3. (2)/(x^2-9) - (3x)/(x^2-5x+6)

4. (x+4)/(x^2-5x+6) / (x^2-16)/(x+3)

What is the probability of throwing several dice with sum equal to 6 (six)? show the ways of possibilities for sum 6 (as the numerator) and the ways of throwing n dices for n = 1, 2, 3, 4 or 5 as denominator for all the questions to earn full credits. (a)throw one die, (b) throw two dice, (c) throw three dice (d) throw 4 dice, (e) throw 5 dice