x/3=y/4 và x mũ 2 +y mũ 2 =100

GIÚP VỚI ĐỀ BÀI LÀ TÌM X,Y

Bài 1 : so sánh

1) A= 1/143+1/99+1/63+...+1/3 và B=199/206

5x(x+2)mũ 2=5/9

Cíu zới

2,5+-7/3x=1/2+x

Viết lại câu sao cho nghĩa không đổi

1. Mary couldn't sing.

-> Mary was .................................

2. When did your father begin to work in that factory?

-> How long ......................................?

3. She started driving two months ago.

-> She has ........................................

4. Our sources of energy will soon end if we don't try to save them.

-> Unless ..........................................

5. These students enjoy reading books.

-> These students are .....................................

Cho dạng đúng của từ trong ngoặc

1. Household waste ................... the environment when not disposed of properly. (pollution)

2. They don't have the ................ to think about their action before they act.           (able)