Подставим \(a = \frac{3}{4}\): \((2 + \frac{3}{4})^2 + (5 - \frac{3}{4})(5 + \frac{3}{4}) = (\frac{8}{4} + \frac{3}{4})^2 + (\frac{20}{4} - \frac{3}{4})(\frac{20}{4} + \frac{3}{4}) = (\frac{11}{4})^2 + (\frac{17}{4})(\frac{23}{4}) = \frac{121}{16} + \frac{391}{16} = \frac{512}{16} = 32. Ответ: 32.