`(x^2 + x)^2 - 14(x^2 + x) + 24`
`= (x^2 + x)^2 - 14(x^2 + x) + 49 - 25`
`= (x^2 + x)^2 - 2. 7(x^2 + x) + 7^2 - 25`
`= (x^2 + x - 7)^2 - 5^2`
`= (x^2 + x - 7 - 5)(x^2 + x - 7 + 5)`
`= (x^2 + x - 12)(x^2 + x -2)`
`= (x^2 - 3x + 4x - 12)(x^2 - x + 2x -2)`
`= [x(x - 3) + 4(x - 3)]. [x(x - 1) + 2(x - 1)]`
`= (x + 4)(x - 3)(x + 2)(x - 1)`