squaring both sides we get
2a^2 + 5a + 2 = 9
2a^2 + 5a - 7 = 0
(2a + 7)(a - 1) = 0
a = -7/2, 1
Checking:-
a = 1:-
(2 + 5 + 2) ^1/2 = 3 so 1 is one solution
a = -7/2 :-
(2(-7/2)^2 + 5(-7/2) + 2)^1/2 = 3 so -7/2 is also a root
So its choice 3
