Ответ:

1) -35y^4x^3

2) -0.04x^6y^8

Объяснение:

5x^2y(-7xy^3) = 5*x^2*y*(-7)*x*y^3 = -35y^4x^3

(-0.2x^3y^4)^2 = (-0.2)^2*(x^3)^2*(y^4)^2 = -0.04x^6y^8