Ineed , i need the factorization of these

12x^2+5x-2

4x^2-4x+1

3x^2-3x-90

There are many ways that you can factor this out. I'd recommend and personally use the grouping method - this way once you get the concept down, you got it and you don't need to guess and check all the time. Another plus is that factoring 4 terms are much easier.

Now, get your hard hats on. Time to factor.

1st: Multiply a and the c term. Now, factor out the number you got from multiplying a and c. The two factors must add up to equal what b is.

12x^2 + 5x - 2 
Factor of 24 that when added equals to 5: 8 and -3 (8 + -3 = 5)

12x^2-3x+8x-2
Now, look at it like this:
12x^2-3x       8x-2 
Then factor each separately:
3x(4x - 1) + 2(4x - 1)

Afterwards, form your answer.
(3x + 2) (4x - 1)

4x^2 - 4x + 1
Factors of 4 (4x1) that when added equal 4: -2 and -2 which equal - 4
4x^2 - 2x - 2x + 1 
2x(2x - 1) - 1 (2x - 1)
(2x - 1)(2x - 1) or (2x - 1)^2

3x^2 - 3x - 90 
Factors of 270 (3x90) that when added equal 3: -18 and 15 which equal - 3
3x^2 + 15x - 18x - 90
3x(x + 5) - 18(x + 5 )
 (3x - 18) (x + 5)