2. Упростите выражение: a) 8+7k-3k+k-11k; б) 4(с - 1) - 7(c-5) - 2(3c + 8); B) (6,5n-3\frac{1}{4}m) - 3,2(\frac{5}{8}n-0,5m).

а) 8 + 7k - 3k + k - 11k = (7 - 3 + 1 - 11)k + 8 = -6k + 8 = -6k

б) 4(c - 1) - 7(c - 5) - 2(3c + 8) = 4c - 4 - 7c + 35 - 6c - 16 = (4 - 7 - 6)c + (-4 + 35 - 16) = -9c + 15

в) \(\frac{4}{13}(6,5n - 3\frac{1}{4}m) - 3,2(\frac{5}{8}n - 0,5m)\) = \(\frac{4}{13}(6,5n - \frac{13}{4}m) - 3,2(\frac{5}{8}n - \frac{1}{2}m)\) = \(\frac{4}{13} \cdot 6,5n - \frac{4}{13} \cdot \frac{13}{4}m - 3,2 \cdot \frac{5}{8}n + 3,2 \cdot \frac{1}{2}m\) = \(2n - m - 2n + 1,6m\) = \(0n + 0,6m\) = 1.4n + 0.2m