40. Упростите выражение и найдите его значение:

Решение:

1. \(3x + 2x = 5x\), при \(x = 0\): \(5 \cdot 0 = 0\)
2. \(7a - 2a = 5a\), при \(a = \frac{1}{5}\): \(5 \cdot \frac{1}{5} = 1\)
3. \(28y - 7y = 21y\), при \(y = 3\): \(21 \cdot 3 = 63\)
4. \(15 + 6x + 2x = 15 + 8x\), при \(x = 7\): \(15 + 8 \cdot 7 = 15 + 56 = 71\)
5. \(45 + 27a - 3a = 45 + 24a\), при \(a = 4\): \(45 + 24 \cdot 4 = 45 + 96 = 141\)
6. \(32 + 21y - 8y = 32 + 13y\), при \(y = 6\): \(32 + 13 \cdot 6 = 32 + 78 = 110\)
7. \(11 - (2x + x) = 11 - 3x\), при \(x = 2\): \(11 - 3 \cdot 2 = 11 - 6 = 5\)
8. \((10a - 8a) - 3 = 2a - 3\), при \(a = 5\): \(2 \cdot 5 - 3 = 10 - 3 = 7\)
9. \(4y + 5y = 9y\), при \(y = 0,1\): \(9 \cdot 0,1 = 0,9\)
10. \(35x + 4x = 39x\), при \(x = 4\): \(39 \cdot 4 = 156\)
11. \(32a + 9a = 41a\), при \(a = 7\): \(41 \cdot 7 = 287\)
12. \(14 + 7y + 3y = 14 + 10y\), при \(y = 5\): \(14 + 10 \cdot 5 = 14 + 50 = 64\)
13. \(27 + 12x - 9x = 27 + 3x\), при \(x = 4\): \(27 + 3 \cdot 4 = 27 + 12 = 39\)
14. \(39 + 15a - 12 = 27 + 15a\), при \(a = 2\): \(27 + 15 \cdot 2 = 27 + 30 = 57\)
15. \(7 + (5y - 3y) = 7 + 2y\), при \(y = 1\): \(7 + 2 \cdot 1 = 7 + 2 = 9\)