Ответ:\(5a^6\cdot(-3a^2b)^2=5a^6\cdot9a^4b^2=45a^{10}b^2\).\((-x^4y^3)^7\cdot8x^2y^5=-x^{28}y^{21}\cdot8x^2y^5=-8x^{30}y^{26}\).