2. Найдите значение выражения (16a²-25b²) : (4a-5b) при a = -³/₄ и b = -¹/₂₀

\[\begin{aligned} \frac{16a^2 - \frac{1}{25b^2}}{4a - \frac{1}{5b}} &= \frac{(4a - \frac{1}{5b})(4a + \frac{1}{5b})}{4a - \frac{1}{5b}} \\ &= 4a + \frac{1}{5b} \end{aligned}\]

\[\begin{aligned} 4a + \frac{1}{5b} &= 4 \cdot (-\frac{3}{4}) + \frac{1}{5 \cdot (-\frac{1}{20})} \\ &= -3 + \frac{1}{-\frac{1}{4}} \\ &= -3 - 4 \\ &= -7 \end{aligned}\]