Final answer:
The sum of all possible values of $a$ is $\frac{8}{5}$.
Step-by-step explanation:
To find the sum of all possible values of $a$, we first need to find the distance between points $A$ and $B$ using the distance formula.
The distance formula is given by:
\(d = \sqrt{ (x_2 - x_1)^2 + (y_2 - y_1)^2 }\)
Using the given coordinates for points $A$ and $B$, we have:
\(d = \sqrt{(2 - a)^2 + (2a - 1 + 1)^2}\)
Expanding and simplifying the expression, we get:
\(d = \sqrt{a^2 - 4a + 4 + 4a^2 - 4a + 1}\)
\(d = \sqrt{5a^2 - 8a + 5}\)
Since the distance between points $A$ and $B$ is given as $\sqrt{5}$, we can equate the expression obtained above to $\sqrt{5}$ and solve for $a$:
\(\sqrt{5a^2 - 8a + 5} = \sqrt{5}\)
Squaring both sides of the equation, we get:
\(5a^2 - 8a + 5 = 5\)
Simplifying further, we have:
\(5a^2 - 8a = 0\)
Factoring out $a$, we get:
\(a(5a - 8) = 0\)
Setting each factor equal to zero and solving, we find two possible values for $a$: $a = 0$ and $a = \frac{8}{5}$.
Therefore, the sum of all possible values of $a$ is $0 + \frac{8}{5} = \frac{8}{5}$.