Answer:
tex]a^2 - 4b \neq 2[/tex]
Step-by-step explanation:
We are given that a and b are integers, then we need to show that 
Let 
If a is an even integer, then it can be written as
, then,

RHS is a fraction but LHS can never be a fraction, thus it is impossible.
If a is an odd integer, then it can be written as
, then,

RHS is a fraction but LHS can never be a fraction, thus it is impossible.
Thus, our assumption was wrong and
.