[tex]\dfrac 2{n-2} + \dfrac 3{(n-2)^2}\\\\\\=\dfrac{2(n-2)+3}{(n-2)^2}\\\\\\=\dfrac{2n-4+3}{(n-2)^2}\\\\\\=\dfrac{2n-1}{(n-2)^2}[/tex]
