Объяснение:
3) (-2a^6*b^3)^3 : (5a^8*b^4)^2 = (-8a^18*b^9) : (25a^16*b^8) =
= -8/25*a^2*b
При a = 7/8, b = 3/25 получаем
-8/25*a^2*b = -8/25*49/64*3/25 = - (49*3)/(8*25^2) = - 147/5000
4) (3a^9*b^3)^2 : (-4a^4*b)^4 = (9a^18*b^6) : (256a^16*b^4) =
= 9/256*a^2*b^2
При a = 5/9, b = -16 получаем
9/256*(5/9)^2*(-16)^2 = 9/256*25/81*256 = 25/9
