Ответ:
2. Приведите подобные слагаемые:
- \( 7a - 19a + 28a - 2a = (7 - 19 + 28 - 2)a = 14a \)
- \( -8x + 16x - 23x + 17x = (-8 + 16 - 23 + 17)x = 2x \)
- \( 2,7m - n + 3,5m - 2,7n = (2,7m + 3,5m) + (-n - 2,7n) = 6,2m - 3,7n \)
- \( 2,9c + 1,8 - 5,2c - 1,2 = (2,9c - 5,2c) + (1,8 - 1,2) = -2,3c + 0,6 \)
- \( 2,6p - 0,7k + 1,3 - 3,1p + 2,8k = (2,6p - 3,1p) + (-0,7k + 2,8k) + 1,3 = -0,5p + 2,1k + 1,3 \)
- \( -\frac{5}{7}a + \frac{4}{9}b + \frac{9}{14}a - \frac{7}{15}b = (-\frac{5}{7}a + \frac{9}{14}a) + (\frac{4}{9}b - \frac{7}{15}b) = (-\frac{10}{14}a + \frac{9}{14}a) + (\frac{20}{45}b - \frac{21}{45}b) = -\frac{1}{14}a - \frac{1}{45}b \)
