1) (3а+b)^3 - (a+3b)^3 - 18ab(a-b) - 26(a^3 - b^3) = 3a^3 + b^3 -a^3 + 3b^3 - 18a^2 b + 18ab^2 - 26a^3 + 26b^3= -24a^3 +30b^3
2) (x+4y)^3 + (4x-y)^3 + 12xy(3x-5y)-128y^3- 65(x^3 - y^3) = x^3 + 4y^3 + 4x^3 - y^3 + 36x^2y - 69xy^2 - 128y^3 - 65x^3+ 65y^3 = -60x^3 - 60y^3 +36x^2y - 69xy^2
А) -(4х-18) +18 = -4х+18+18 = -4х+36
б) (5-2b) - (7+10b) = 5-2b-7-10b=-2-12b
B) -(3c+5x)-(9c-6x)= -3c-5x-9c+5x+ -11x
Г) (2a-7y)-(5a-7y)= 2a-7y-5a+7y=-3a
Д)(11p+9c)-(12+11+9c) + 11p+9c -12 -11p-9c+= -12
e) x-(x-15)+(13+x)=x-x+15+13+x=x+28
Ж) (3а-21)-2а-(17-8а)= 3а-21-2а-17+8а=9а-38
з) (2-4b)-(31b-6)-11= 2-4b-31b+6-11= -35b-3
е) 14b-(15b+y)-(y+10b)= 14b -15b-y-y-10b=-11b-2y