Question

refer to the attachment
wrong answer will be reported​

Answer 1

Answer:

valence electron is an outer shell electron that is associated with an atom, and that can participate in the formation of a chemical bond if the outer shell is not closed; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.

Answer 2

Answer:

If x=a,y=b is the solution of the equations x−y=2 and x+y=4, then the values of a and b are, respectively:

3 and 1