No
x^2 + 4x + 5 cannot be factored because its discriminant is less than zero.
(4x - 7y)(4x + 7y)
x(x-4)
8x2 + 6x - 9 = 8x2 + 12x - 6x - 9 = 4x(2x + 3) - 3(2x + 3) = (2x + 3)(4x - 3)
There is no rational factorisation.
(4x - 3)(2x + 3)
7x2 -4x -5x2 +2x = 2x2 -2x
4x + 20
-x2+2x
(2x - 9)(2x - 9) or (2x - 9)2
4x2+4x-8 4(x2+x-2) and (4x+8)(x-1)
x - 2
x2 - 4x - 21 = (x-7)(x+3)
No
2x(2x - 1)
(2x - 1)(4x + 1)