67 + 24 = 67 + 3 + 20 = 70 + 20 = 90
48 + 15 = 48 + 2 + 13 = 50 + 13 = 63
26 + 39 + 17 = 39 + 1 + 26 + 4 + 12 = 40 + 30 + 12 = 82
18 + 68 + 9 = 68 + 2 + 18 + 2 + 5 = 70 + 20 + 5 = 95
.................................................нет
Использованы свойства логарифмов
3a-3b-2a-2b=3a-2a-3b-2b=1a-1b
4x+4y+10x-5y=4x+10x-5y+4y=14x-1y