Question

thực hiện phép tính :(y+3)^3-(3-y)^2-54y

Answer 1

`(y+3)^3-(3-y)^2-54y`

`=y^3+9y^2+27y+27-9+6y-y^2-54y`

`=y^3+8y^2-21y+18`

 

Answer 2

Ta có: \(\left(y+3\right)^3-\left(3-y\right)^2-54y\)

\(=y^3+9y^2+27y+27-\left(y^2-6y+9\right)-54y\)

\(=y^3+9y^2-27y+27-y^2+6y-9\)

\(=y^3+8y^2-21y+18\)