a) \(3\times\dfrac{4}{11}=\dfrac{3\times4}{11}=\dfrac{12}{11}\)

b) \(1\times\dfrac{5}{4}=\dfrac{1\times5}{4}=\dfrac{5}{4}\)

c) \(0\times\dfrac{2}{5}=\dfrac{0\times2}{5}=\dfrac{0}{5}=0\)

a: \(=\dfrac{3\cdot4}{11}=\dfrac{12}{11}\)

b: \(=\dfrac{1\cdot5}{4}=\dfrac{5}{4}\)

c: \(=\dfrac{0\cdot2}{5}=0\)

=1 đó bạn ạ

x = 1 nha !

\(2.2^2.2^3.2^4....2^x=1024=2^{10}\)

\(\Rightarrow2^{1+2+3+\text{4+}...+x}=2^{10}\)

\(\Rightarrow1+2+3+4+...+x=10\)

\(\Rightarrow1+2+3+4+...x=1+2+3+4\)=>x=4

TA CÓ 1024=2^10

SUY RA X=0 

1x2/1+2 + ... + 1x2x ... x 999x1000/1+2+ ... +1000

= 1 + ... + 1

= 1 x 1000

= 1000

=\(\frac{1}{96}\)​​

Đúng 100 %

\(\frac{1.2.6.4.6.4.5.2}{2.3.6.8.6.2.2.2.8.10}=\frac{1}{96}\)

Gía trị của biểu thức là : \(\frac{1x2x3x2x2x2x2x3x2x2x2x5x2}{2x3x3x2x4x2x3x2x2x2x2x4x2x5x2}\)= \(\frac{1}{48}\)

2x2²x2³.....x2^x=32768=2¹⁵

=>2^1+2+3+...+x=2¹⁵ =>1+2+3+...+x=15

=>\(\dfrac{x\left(x+1\right)}{2}=15=>x\left(x+1\right)=30=5.\left(5+1\right)\)

=>x=5

sao không ai trả lời vậy ?

Bài 3: 

\(A=2\left(1+2\right)+2^3\left(1+2\right)+...+2^{59}\left(1+2\right)\)

\(=3\left(2+2^3+...+2^{59}\right)⋮3\)

\(A=2\left(1+2+2^2\right)+2^4\left(1+2+2^2\right)+...+2^{58}\left(1+2+2^2\right)\)

\(=7\left(2+2^4+...+2^{58}\right)⋮7\)

\(A=2\left(1+2+2^2+2^3\right)+2^5\left(1+2+2^2+2^3\right)+...+2^{57}\left(1+2+2^2+2^3\right)\)

\(=15\left(2+2^5+...+2^{57}\right)⋮15\)