Ph©n tÝch ®a thøc sau thµnh nh©n tö:
1/ 7x + 7y
2/ 2x
2
y – 6xy
2
3/ 3x(x – 1) + 7x
2
( x – 1)
4/ 3x(x – a) + 5a(a – x)
5/ 6x
4
– 9x
3
6/ 5y
10
+ 15y
6
7/ 9x
2
y
2
+ 15x
2
y – 21xy
2
8/ x
2
y
2
z + xy

(x
2
+ y) – zx
2
– zy
17/ 4x(x – 2y) + 8y(2y – x)
18/ 3x(x + 1)
2
– 5x
2
(x + 1) + 7(x + 1)
19/ 2x + 1)
2
– (x – 1)
2

20/ 9(x + 5)
2
– (x – 7)
2
21/ 25(x – y)
2
– 16(x + y)
2
22/ 49(y – 4)
2
– 9(y + 2)
2
23/ x
4

2
– 12y
2
30/ 5xy
2
– 10xyz + 5xz
2
31/ x
3
+ 3x
2
+ 3x + 1 – 27z
3
32/ x
2
– 2xy + y
2
– xz + yz
33/ x
2
– y
2
– x + y
34/ a
3
x – ab + b – x
35/ 3x
2
(a + b + c) + 36xy(a + b + c) + 108y
2

2
- 8)
2
+ 36