a) 25x2 - 20xy + 4y2
= (5x)2 - 2.5x.2y + (2y)2
= (5x - 2y)2
b) x2 - 6x + 8
= x2 - 6x + 9 - 1
= (x - 3)2 - 1
= (x - 3 - 1)(x - 3 + 1)
= (x - 4)(x - 2)
c) x2 - 5x - 14
= x2 + 2x - 7x - 14
= (x2 + 2x) - (7x + 14)
= x(x + 2) - 7(x + 2)
= (x - 7)(x+2)
d) x5 - x
= x(x4 - 1)
= x(x2 + 1)(x2 - 1)
= x(x2 + 1)(x - 1)(x + 1)
e) x3 - 3x2 - 4x + 12
= (x3 - 3x2) - (4x - 12)
= x2(x - 3) - 4(x - 3)
= (x2 - 4)(x - 3)
1) 25x2-20xy+4y2
=(5x)2-20xy+(2y)2
=(5x-2)2
2) x2-6x+8
=x2-2x-4x+8
=x(x-2)-4(x-2)
= (x-4)(x-2)
3) x2-5x-14
=x2+2x-7x-14
=x(x+2)-7(x+2)
=(x-7)(x+2)
4) x5-x
=x(x4-1)
5) x3-3x2-4x+12
=x3+2x2-5x2-10x+6x+12
=(x3+2x2)-(5x2+10x)+(6x+12)
=x2(x+2)-5x(x+2)+6(x+2)
=(x+2)(x2-5x+6)
=(x+2)(x2-2x-3x+6)
=(x+2)[x(x-2)-3(x-2)]
=(x+2)(x-3)(x-2)
nếu bn có chỗ nào ko hiểu thì cứ bảo vs mik nhé, mik hướng dẫn lại cho
nhớ tik cho mik nhá, đừng có xem qua thôi đâu nhé
