a) (x + 2) (x ² – 2x + 4) – x(x ²+ 2)=15 b) (x + 3) ³ – x (3x +1) ² + (2x +1) (4x ² – 2x +1) c) (x ² -1) ³ – (x^4 + x ² + 1) (x ² – 1) =0 tìm x ạ
a) (x + 2) (x ² – 2x + 4) – x(x ²+ 2)=15 b) (x + 3) ³ – x (3x +1) ² + (2x +1) (4x ² – 2x +1) c) (x ² -1) ³ – (x^4 + x ² + 1) (x ² – 1) =0 tìm x ạ