Find the coefficient of y^4 in the expansion of (2y-5+3y^2)^6.
expand (2y-5+3y^2)^6
729 y^12 + 2916 y^11 - 2430 y^10 - 19980 y^9 + 135 y^8 + 59976 y^7 + 6364 y^6 - 99960 y^5 + 375 y^4 + 92500 y^3 - 18750 y^2 - 37500 y + 15625
The coefficient of y^4 ==+ 375
