For this case, we have by definition, that an irrational number is a number that can not be expressed as a fraction
, where a and b are integers and b is nonzero.
Some examples are:

So, that the answer is 
Answer:
Option C
3x2+4(-1)-2(5)2 +4(5)+5=
__________________
6+-4-10+25
_________
31-14=17
C and D
Hope this helps !
They will each get 1/6 of the pizza.