(i) The polynomials can be factored as,
[tex]\begin{gathered} x^2-5x-24 \\ =x^2-8x+3x-24 \\ =x(x-8)+3(x-8) \\ =(x-8)(x+3) \end{gathered}[/tex](ii)
[tex]\begin{gathered} 9x^2-12x+4 \\ =(3x)^2-2\times(3x)\times2+(2)^2 \\ =(3x-2)^2 \\ =(3x-2)(3x-2) \end{gathered}[/tex](iii)
[tex]\begin{gathered} 16x^2-49 \\ =(4x)^2-(7)^2 \\ =(4x-7)(4x+7) \end{gathered}[/tex]