TL

X - \(\frac{1}{4} = \frac{7}{2} x \frac{-3}{5}\)

X - \(\frac{1}{4}=\frac{-21}{10}\)

              X       =\(\frac{-21}{10} + /frac{1}{4}\)

             X       =\frac{-37}{20}\)

nha bn

HT

TL

\(\frac{x+5}{36} = \frac{4}{x+5}\)

=> (x+5)(x+5)=36x4

=> (x+5)^2=144

=>(x+5)^2=12^2 hoặc (x+5)=-12^2

=>x+5=12                  x+5=-12

=>   x=12-5                    x=-12-5

=>  x=7                          x=-17

HT

\(\dfrac{x+5}{36}=\dfrac{4}{x+5}\\ \Rightarrow\left(x+5\right)^2=144\\ \Rightarrow\left[{}\begin{matrix}x+5=12\\x+5=-12\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=7\\x=-17\end{matrix}\right.\)

= 7/20 nha mik cx ko bt 

\(x\left(5-x\right)^{2018}-\left(5-x\right)^{2019}=0\)

\(\Leftrightarrow\left(5-x\right)^{2018}\left[x-\left(5-x\right)\right]=0\Leftrightarrow\left(5-x\right)^{2018}\left(2x-5\right)=0\Leftrightarrow x=5;x=\dfrac{5}{2}\)

= -20 nhé

\(-4\times5=-20\)

@muối

26/42 = 13/21

56/78 = 28/36 = 7/9 

Mà 13/21 = 117/189, 7/9 = 91/189

Nên : 26/42 > 56/78

\(A=3+3^2+3^3+...+3^{100}\)

\(\Rightarrow3A=3^2+3^3+3^4+...+3^{101}\)

\(3A-A=3^{101}+3^{100}+3^{99}+...+3^2-3^{100}-3^{99}-...-3\)

\(2A=3^{101}-3\)

Ta thấy \(3^{101}-3< 3^{101}-1\)hay 2A<B=>A< B.