How do I factor these:

2x2 - 16x + 30
4x^2-9
x^2-5x
5x^2-26x+5
25x^2+4

Example:

2x^2 - 16x + 30 =

2 (x^2 - 8 x + 15)

2(x - 5)(x - 3)

The first, factor out a 2 first. Then factor .
The second...difference of two squares
Third factor out an x

I will be happy to critique your work. You need to do some trial and error.