1) 3xy - x^3y^3 - 6 + 2x^2y^2, при x =

1) 2х^2у^2-х^3у^3-6+3ху=х^2у^2(2-ху)-3(2-ху)=
(2-ху)(х^2у^2-3);
при х=2/3, у=-3/4;
(2-(-2/3*3/4))(4/9*9/16-3)= (2+2/4)(4/16-3)= (2+1/2)(1/4-3)= 5/2*(-11/4)= -55/8= -6 целых 7/8;
2) 12м^3-10п^2+42м^2п-35п^3=
12м^3+42м^2п-10п^2м-35п^3=
6м^2(2м+7п)-5п^2(2м+7п)=
(2м+7п)(6м^2-5п^2);