(4ĐIỂM) A) X3+X2 + X +1 = X2 (X+1) + (X+1) = (X+1)(X2 +1) (2ĐIỂM)B)...
Bài 1:(4điểm) a) x
3
+
x
2
+ x +1 = x2
(x+1) + (x+1) = (x+1)(x2
+1) (2điểm)b) 6x – 9 – x2
= -(9 - 6x + x2
)+ y2
= (y – 3 + x)(y – 3 - x) (2điểm)3
+
x
2
+ x +1 = x2
(x+1) + (x+1) = (x+1)(x2
+1) (2điểm)b) 6x – 9 – x2
= -(9 - 6x + x2
)+ y2
= (y – 3 + x)(y – 3 - x) (2điểm)