For each function below, determine whether or not the function is injective and whether or not the function is surjective. be sure to justify your answers.
(b) f: p({1,2,3}) + n given by f(a) = |a| (note: p(s) denotes the power set of a set s.)

The function is neither injective nor surjective

Step-by-step explanation:

f: P({1,2,3}) -> N is given by f(A) = |A|

where P(S) denotes the power set of a set S and |A| the number of elements of A

The function is not injective, for  

but  

The function is not surjective either, because 5 is a natural number which is not the image of any element A under f, i.e., there is no element in A in P({1,2,3}) such that f(A)=5

typically if you want , you would actually put questions here for us to you. but hey, that's just me. maybe someone will magically answer the questions for you without knowing what they are.

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons