That cannot be factored
x3 + x2 + 4x + 4 = (x2 + 4)(x + 1)
Not factorable
x + 4
x2 - 2 + 4 = x2 + 2This term can not be factored any further
x2 + 6x + 8 = (x + 4)(x + 2)
(x-1)(x+4)
x2 + 13x + 36 = (x + 9)(x + 4)
(x + 4)(x + 8)
(x + 4)(x + 13)
(x + 4)(x + 9)
Factor it out: (x+2) squared
x2-5x+4 = (x-1)(x-4) when factored