\(28\dfrac{289}{293}=\dfrac{28\times293+289}{293}=\dfrac{8493}{293}\)

cảm ơn

Tìm \(x;\) y nguyên hay như nào em nhỉ?

Dạ x,y thuộc Z ạ

Which class are you in?

How many rooms does your house have?

How many people are there in your family?

Where is your house?

What time is it?

Which class are you in?

- I'm in class 6/1  

How many rooms does your house have?

- My house has three rooms.

How many people are there in your family?

- There are five people in my  family.

Where is your house?

- My house is in the city.

What time is it?

- It's half past nine.

\(#FallenAngel\)

\(A=8abc+4\left(ab+bc+ca\right)+2\left(a+b+c\right)+1\\= 8abc+4ab+4bc+4ca+2a+2b+2c+1\\ =\left(8abc+4ab\right)+\left(4bc+2b\right)+\left(4ca+2a\right)+\left(2c+1\right)\\ =4ab\left(2c+1\right)+2b\left(2c+1\right)+2a\left(2c+1\right)+\left(2c+1\right)\\ =\left(2c+1\right)\left(4ab+2b+2a+1\right)\\ =\left(2c+1\right)\left[\left(4ab+2b\right)+\left(2a+1\right)\right]\\ =\left(2c+1\right)\left[2b\left(2a+1\right)+\left(2a+1\right)\right]\\ =\left(2c+1\right)\left(2a+1\right)\left(2b+1\right)\)

This is my mother, she is a nurse.

This is my mother, she is a nurse.

Lưu ý: my chữ không phải mỹ bạn nhé!

\(#FallenAngel\)

a, A''Có đúng 2 nữ''

\(C^2_3.C_{56}^2\)

\(P\left(A\right)=\dfrac{C_3^2.C_{56}^2}{C_{59}^4}\)

b, B''Có ít nhất 2 nam''

TH1 : Có 2 nam \(C_{56}^2.C_3^2\)

TH2 : Có 3 nam \(C_{56}^3.C_3^1\)

TH3 : Có 4 nam \(C^4_{56}\)

\(\Rightarrow C_{56}^2.C_3^2+C_{56}^3.C_3^1+C_{56}^4\)

\(P\left(B\right)=\dfrac{C_{56}^2.C_3^2+C_{56}^3.C_3^1+C_{56}^4}{C_{59}^4}\)

c, C''Có nhiều nhất 2 nam''

TH1 : Có 1 nam \(C_{56}^1.C_3^3\)

TH2 : Có 2 nam \(C_{56}^2.C_3^2\)

\(\Rightarrow C_{56}^2.C_3^3+C_{56}^2.C_3^2\)

\(P\left(C\right)=\dfrac{C_{56}^2.C_3^3+C^2_{56}.C_3^2}{C_{59}^4}\)

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