5. Упростите выражения: a) (-2x)^4y^2 * (7xy)^3. b) (-mn^2)^4 * (-2m^5n)^2 * (m^5)^3 * (6n^4)^2.

a) (-2)^4 * x^4 * y^2 * (7^3 * x^3 * y^3) = 16 * x^7 * y^5 * 343 = 5488x^7y^5. b) (-1)^4 * m^4 * n^8 * 4 * m^10 * n^2 * m^15 * 36 * n^8 = 144m^(4+10+15) * n^(8+2+8) = 144m^29n^18.