Решите неравенство 1)(y+7)^3-y^3-21y^2>=0

Question

Решите неравенство 1)(y+7)^3-y^3-21y^2>=0

Answer 1

(y+7)^3-y^3-21y^2>=0
y³+21y²+147y+343-y³-21y²≥0
147y>-343
3y>-7
y>-7/3
y>-2 1/3