a) 9(7x - 6) - 18x
\(9 \cdot 7x - 9 \cdot 6 - 18x = 63x - 54 - 18x\)
\(63x - 18x - 54 = 45x - 54\)
Ответ: \(45x - 54\)
б) 7a - 6(19 - a)
\(7a - 6 \cdot 19 + 6 \cdot a = 7a - 114 + 6a\)
\(7a + 6a - 114 = 13a - 114\)
Ответ: \(13a - 114\)
в) 0,8(6x - 2) + 1,6(x - 4)
\(0.8 \cdot 6x - 0.8 \cdot 2 + 1.6 \cdot x - 1.6 \cdot 4 = 4.8x - 1.6 + 1.6x - 6.4\)
\(4.8x + 1.6x - 1.6 - 6.4 = 6.4x - 8\)
Ответ: \(6.4x - 8\)
г) 2,8(5b - 6a) - 12(7b - 8a)
\(2.8 \cdot 5b - 2.8 \cdot 6a - 12 \cdot 7b + 12 \cdot 8a = 14b - 16.8a - 84b + 96a\)
\(14b - 84b - 16.8a + 96a = -70b + 79.2a\)
Ответ: \(79.2a - 70b\)
д) -(-4,9 - 5,8c) - (3,1c - 5,6)
\(4.9 + 5.8c - 3.1c + 5.6\)
\(5.8c - 3.1c + 4.9 + 5.6 = 2.7c + 10.5\)
Ответ: \(2.7c + 10.5\)