Cho tam giác ABC cân tại A Gọi M là trung điểm của BC 
a, Chứng minh tam giác AMB = tam giác AMC, Chứng minh rằng AM vuông góc với BC 
b, Trên tia đối của tia MA lấy điểm K sao cho MA=MK Chứng minh AB // CK
c, Chứng minh AC = BK
d, Trên cạnh AB lấy điểm E, trên cạnh CK lấy điểm F sao cho AE = KF. Chứng minh 3 điểm E,M,F thẳng hàng

\(a,\dfrac{-2}{3}.\left[\left(7,2-\dfrac{2}{5}\right).x-\dfrac{3}{13}\right]=1\dfrac{1}{15}\)

\(a,2.\left(x-\dfrac{1}{2}\right)-5.\left(x+\dfrac{3}{5}\right)=-x+\dfrac{1}{3}\)

\(b,x\left(x-\dfrac{1}{3}\right)-\dfrac{1}{2}x\left(2x-3\right)=\dfrac{1}{4}\)

\(a,\dfrac{7}{12}-\dfrac{1}{4}:\left(\dfrac{-4}{11}-x\right)=-125\%\)

\(b,\left(x-\sqrt{\dfrac{49}{169}}\right):2\dfrac{3}{11}+0,6=0,16\)

\(c,\dfrac{-2}{3}-\left[\left(7,2-\dfrac{2}{5}\right).x-\dfrac{3}{13}\right]=1\dfrac{1}{15}\)

I. Rewrite sentences , using compound words.

6. This is a farm which grows vegetables.

7. It is a company which imports sugar.

8. Vietnam is a country which exports coffee.

9. It is a festival in which people have to cut rice.

10. It is a contest in which participants have to cook rice.

11. It is a contest in which participants have to make fire.

I. Rewrite sentences , using compound words.

1. Vietnam is a country which exports a lot of rice.

2. Honda is a company which produces motorbikes.

3. It is a farm which raises chicken

 4. Last month my club held a contest in which members spoke English as fluently as they could.

5. Last week our school held a contest in which students arranged flowers.