How do I factor

4x^2 + 8x + 4

Alll I have iz (4x+4)(x+4)
and I know its wrong

how do i factor

8X^2+10X-3

I know the answer is
(4X-1)(2X+3)
I just guessed and checked
not sure about thorught process that's suppose to go trough my head here when dealing with a number before X^2 please tell me

cuz i can get the answer by guessing but that takes to long