[tex]2x- \dfrac{3}{x} : \dfrac{7}{x^2} =2x-\dfrac{3}{x}\cdot \dfrac{x^2}{7} =2x- \dfrac{3}{7} x=(2- \dfrac{3}{7} )x= \dfrac{2\cdot7-3}{7} x= \dfrac{11}{7} x[/tex] (this is what is given in task)
Note that [tex]\dfrac{3}{x} : \dfrac{7}{x^2} =\dfrac{3}{x}\cdot \dfrac{x^2}{7} = \dfrac{3x^2}{7x} = \dfrac{3x}{7} = \dfrac{3}{7} x[/tex].