Sửa đề: \(\left(\dfrac{1}{3}+\dfrac{3}{4}-\dfrac{13}{12}\right):\left(\dfrac{12}{23}+\dfrac{123}{234}+\dfrac{1234}{2345}\right)\)

\(=\left(\dfrac{4+9-13}{12}\right):\left(\dfrac{12}{23}+\dfrac{123}{234}+\dfrac{1234}{2345}\right)\)

=0

\(\left(\frac{1}{3}+\frac{3}{4}-\frac{13}{12}\right):\left(\frac{12}{13}+\frac{123}{234}+\frac{1234}{2345}\right)\)

\(=\left(\frac{4}{12}+\frac{9}{12}-\frac{13}{12}\right):\left(\frac{12}{13}+\frac{123}{234}+\frac{1234}{2345}\right)\)

\(=\left(\frac{4+9-13}{12}\right):\left(\frac{12}{13}+\frac{123}{234}+\frac{1234}{2345}\right)\)

\(=0:\left(\frac{12}{13}+\frac{123}{234}+\frac{1234}{2345}\right)\)

\(=0\)

Study well ! >_<

(13 +34  - 1312  ) : (1213  + 123234  +12342345  )

=\(\left(\frac{4}{12}+\frac{9}{12}-\frac{13}{12}\right):\left(\frac{12}{13}+\frac{123}{234}+\frac{1234}{2345}\right)\)

= \(\left(\frac{4+9-13}{12}\right):\left(\frac{12}{13}+\frac{123}{234}+\frac{1234}{2345}\right)\)

= \(0:\left(\frac{12}{13}+\frac{123}{234}+\frac{1234}{2345}\right)\)

\(=0\)

234+(-1234) 

= 234+(-1000-234)

= 234-1000-234

=-1000

\(\text{234+(-1234) }\)

\(\text{= 234 - 1234}\)

\(\text{= -1000}\)

😊

>

gọi 987²³⁴+987²³⁵+987²³⁶ là m ta có

A=m+7896/m-4935=m-4935+12831/m-4935=1+12831/m-4935

B cũng làm như trên ra bằng 1+12831/m-5922

ta có m-4935>m-5922

=.>A<B

A BÉ HƠN B NHA