[tex] \dfrac{2k}{3k-7} - \dfrac{3}{8k} = \dfrac{8k(2k)}{8k(3k-7)} - \dfrac{3(3k-7)}{8k(3k-7)} = \dfrac{8k(2k)-3(3k-7) }{8k(3k-7)} = \dfrac{16k^2 - 9k + 21}{24k^2-56} [/tex]
