3,9хb¹⁴ * (-5)хbd - 4,55kn * 15k³n = -19,5x²b¹⁵d - 68,25k⁴n²
3m8y - 2n3b - 0,2y12m + b12n - 12ym + 13nb =
= 24my - 6nb - 2,4my + 12nb - 12my + 13nb = 9,6my + 19nb,
(18 4/5 а - 2/13 а²) + (1/13 а² - 1 4/5 а) = 18 4/5 а - 2/13 а² + 1/13 а² - 1 4/5 а =
= (18 4/5 а - 1 4/5 а) - (2/13 а² - 1/13 а²) = 17а - 1/13 а²