ПОМОГИТЕ ПОЖАЛУЙСТА С ПРИМЕРОМ [latex] \frac{7}{a} - \frac{-10 a^{2} -11 b^{2} }{ab} - \frac{10a}{b} [/latex]

[latex]\dfrac{7}{a} - \dfrac{-10 a^{2} -11 b^{2} }{ab} - \dfrac{10a}{b} = \dfrac{7}{a} + \dfrac{10 a^{2} +11 b^{2} }{ab} - \dfrac{10a}{b} = \\\\ =\dfrac{7b}{ab} + \dfrac{10 a^{2} +11 b^{2} }{ab} - \dfrac{10a^2}{ab} = \dfrac{7b+10 a^{2} +11 b^{2}-10a^2}{ab} = \\\\ =\dfrac{7b +11 b^{2}}{ab} =\dfrac{b(7 +11 b)}{ab} =\dfrac{7 +11 b}{a} [/latex]