We can just factorize it :)
4a^2 - 10a + 6 = 0
2a^2 - 5a + 3 = 0
(2a - something)(a - something)=0
We don't know what it is yet, but think of 2 numbers that satisfies:
−2x−y=−5xy=3
We can easily see that x = 1 and y = 3.
(2a - 3)(a - 1) = 0
a = 3/2 or a = 1 :)