VỚI MỌI X,Y,Z THÌ X2 + Y2 + Z2 XY+ YZ+ ZX. 2 2 2A +B A+B ....
Câu 1. (x−1)(x
2
−2x+2) bằng: A. x3
−x2
+4x−2.
B. x3
−3x2
−2.
C. x3
−3x2
−4x−2 . D. x3
−3x2
+4x−2.
2
−2x+2) bằng: A. x3
−x2
+4x−2.
B. x3
−3x2
−2.
C. x3
−3x2
−4x−2 . D. x3
−3x2
+4x−2.