K4 in women's pants are size 4 in the US. K4 is a known to be a size 5 in the UK and 22 in the EU.
Not factorable
(2x + 1)(x + 4)
a2 - 4a + 4
(2x+4)(x+1)
(3x + 4)(3x + 4)
4(x + 1)(x + 1)
(x-1)(x+4)
That's 44v + 4 which factors to 4(11v + 1)
x3 + x2 + 4x + 4 = (x2 + 4)(x + 1)
x3 + 4x2 + x + 4 = (x + 4)(x2 + 1)
(b + 4)(b + 4)