A) X X  3 X2 0 B) 3X 4 X24X0LỜI GIẢI A) 2X 1 Y X 1 X1 2 YB) X216X242 X4X4C) 7X312X24X X 7X212X4 X 7X214X2X4X7X X 2 2 X2 2 7 2  X X X

2) Tìm x biết: a) x x

 3

x

2

0 b) 3

x 4

x

2

4x0Lời giải a) 2

x 1

 

y x 1

 

x1 2



y

b) x

2

16x

2

4

2

x4



x4

c) 7x

3

12x

2

4x x

7x

2

12x4

 

x 7x

2

14x2x4

x7x x

2

 

2 x2

2 7



2

  x x x