b6 fashion - long hours - contacted  - clients - grades 

b5 c làm ở dưới r í

Bài 4 nào bài 8 đâu em 

là sao

chắc lại bị lỗi rồi

19d

20a

#\(Cụt cạp cạp\)

#\(yGLinh\)

???

Bài nào :>

lỗi r

Mình cần gấp ạ

\(13,=\dfrac{\sqrt{3}\left(\sqrt{6}-2\right)}{\sqrt{6}-2}+\dfrac{4\left(\sqrt{3}-1\right)}{2}+12-3\sqrt{3}\\ =\sqrt{3}+2\sqrt{3}-2+12-3\sqrt{3}=10\\ 14,=\dfrac{12\left(4+\sqrt{10}\right)}{6}-3\sqrt{10}+\dfrac{\sqrt{10}\left(\sqrt{5}+1\right)}{\sqrt{5}+1}\\ =8+2\sqrt{10}-3\sqrt{10}+\sqrt{10}=8\\ 15,=\dfrac{2x-6\sqrt{x}+x+3\sqrt{x}-3x-9}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}\\ =\dfrac{-3\left(\sqrt{x}+3\right)}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}=\dfrac{-3}{\sqrt{x}-3}\)

\(16,=\dfrac{x+2\sqrt{x}-3-x+3\sqrt{x}-4\sqrt{x}-6}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\\ =\dfrac{\sqrt{x}-9}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\\ 17,=\dfrac{x+3\sqrt{x}+2+2x-4\sqrt{x}-5\sqrt{x}-2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}\\ =\dfrac{3\sqrt{x}\left(\sqrt{x}-2\right)}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}=\dfrac{3\sqrt{x}}{\sqrt{x}+2}\)

b) 

Đặt : CT : B_xO_y

\(\dfrac{\%B}{\%O}=\dfrac{Bx}{16y}=\dfrac{7}{3}\)

\(\Leftrightarrow Bx=\dfrac{112}{3}y\)

\(BL:x=2,y=3\)

\(\Rightarrow B=56\)

\(CT:Fe_2O_3\)

30) a ) 

Đặt : CT: M_xO_y

\(TC:\)

\(\dfrac{xM}{16y}=\dfrac{9}{8}\)

\(\Leftrightarrow xM=18y\)

\(BL:x=2,y=3\)

\(\Rightarrow M=27\)

\(CT:Al_2O_3\)

Bài 3:

Diện tích khu vườn là:

\(\left(35:5\cdot1\right)\cdot\left(35:5\cdot6\right)=294\left(m^2\right)\)

III

1 a

2 an

3 a

4 an

5 an

6 some

7 any

8 some

9 any

10 an