A fraction isn't always rational. Now usually numbers like

e, Eulers number
The Golden Ratio

These would be considered Irrational. Although the answer for this is a rational number (a number that has an end, or can be written out to put it simply.).
I hope this helped :)
P(BB)=(4/12)(3/11)=12/132=1/11
P(RG)=(3/12)(5/11)=15/132=5/44
The provided equation is not an identity
Just take a calculator and divide 4 by 10 exactly how you see it. Or just divide it like you normally would any number on paper. 0.4 is your answer.
C. x³ - x²
In word problems, there terms which indicate the mathematical operation that needs to be performed.
difference = refers to the answer in subtraction
triple a number or double a number refers to the number of times a number is multiplied by itself.
in triple a number = a number is multiplied by itself three times.
in double a number = a number is multiplied by itself two times.
It would initially look like this: (x * x * x) - (x * x); to simplify the expression, a number to be multiplied is written down and the number of times it will multiply by itself is noted on the upper right side of the number when we look at it.
Thus: x³ - x² is the correct expression that best describes the word problem above.