Tỉ số phần trăm lượng muối trong nước biển là:

         2,8 : 80 = 0,035 = 3,5%

                 Đ/S: 3,5%

\(\sqrt{900}=30\)

\(a^2-b^2=\left(a-b\right)\left(a+b\right)\)

\(x^4+4=x^4+4x^2+4-4x^2\)

\(=\left(x^2+2\right)^2-4x^2\)

\(\left(x^2+2-2x\right)\left(x+2+2x\right)\)

BC(2,3,4,5,6) = {60 ; 120 ; 180 ; 240 ; 300 ; ...}

Vì số trứng trong rổ chia cho 2,3,4,5,6 đều dư 1 quả nên khả năng kết quả (BC của 2,3,4,5,6 cộng thêm 1) sẽ là: 60 ; 121 ; 181 ; ...

Khi thử chia các số nhỏ hơn 400 ở trên cho 7 thì chỉ có 301 là chia hết cho 7.

Vậy trong rổ có 301 quả trứng.

cho mk nhé

tỏng số viên bi của 2 túi là:

35+24=59(viên bi)

Nếu bn thấy đúng thì tk cho mk vs nha

1+1=2 nhé Nguyễn Mạnh Hùng

x²=4x <=>x²-4x=0

<=>x(x-4)=0

<=>x=0 hoặc x-4=0

1. We are polluting our environment without knowing that effect they may have on our life.

-> ∅

2. Unemployment is a very large problem with which most countries have come to face with.

-> deal

3.Million of people live day on day with little or even no money.

-> day by day

4. When the unemployers have nothing to do, they will feel bored and hopeless.

-> unemployed

5. The most important thing is that we should study hardly for our life.

-> hard

6. Money is that she wants from him.

-> what ( the thing which)

7. Your computer, that you lent me, doesn't work properly.

-> which

8. Nam is not enough intelligent to solve this mathematic question without help.

-> intelligent enough

9. Two of these tablets should be taken day before your meal.

-> before

10. Just look at Long! He seems so cheerfully today.

-> cheerful

Theo đầu bài ta có:
\(1+2+4+8+16+32+...+1024+2048+4096\)
\(\Leftrightarrow2^0+2^1+2^2+2^3+2^4+2^5+...+2^{10}+2^{11}+2^{12}\)
\(\Leftrightarrow2\left(2^0+2^1+2^2+...+2^{11}+2^{12}\right)-\left(2^0+2^1+2^2+...+2^{11}+2^{12}\right)\)
\(\Leftrightarrow\left(2^1+2^2+2^3+...+2^{12}+2^{13}\right)-\left(2^0+2^1+2^2+...+2^{11}+2^{12}\right)\)
\(\Leftrightarrow2^{13}-2^0=8192-1=8191\)