Nothing here to "SOLVE." Plus, you don't have to go through all of what that person went through to Factorize this trinomial
2x2 + 3x - 2
2x2 + 4x - x - 2 ------ Replacing 3x with + 4x - x
2x2 + 4x - x - 2
2x(x + 2) - 1(x + 2)
(2x - 1)(x + 2) <===== Factorized form
That's IT!! Nothing more, nothing less!