Помогите решить 8 примеров пж мне надо завтра здать

1) 0,7a^2y (- 0.8a^5y^10) = -0.56a^7y^11 2) -0.4a^5(-5a^3)^4 = -0.4a^5 (625a^12) = - 250a17 3) (3x^7y^3)^4* 1/81xy = (81x^28y^12) * 1/81xy + x^29y^13 4)(3y^2 +3y -4) - (y^2 - 2y + 7) = 3y^2 + 3y - 4 - y^2 + 2y - 7 = 2y^2 + 4y -11 5) 2c(c^2 + 3c) = 2c^3 + 6c^2 6) (x + 4)(x^2 + 2x - 3) = x^3 + 2x^2 - 3x + 4x^2 + 8x - 12 = x^3 + 6x^2 + 5x - 12 7) (x + 1)(x^2 - 3) - x^3 = x^3 - 3x + x^2 - 3 = x^3 + x^2 - 3x - 3 8) (15x^2y + 10xy) /(1/5xy) = 75x + 50