\(\frac{2}{5}-3x^2bang\frac{9}{25}\)

1. \(x^2+2y^2+2xy-2y+1=0\)

\(\left(x+y\right)^2+y^2-2y+1=0\)

\(\left(x+y\right)^2+\left(y-1\right)^2=0\)

Có: \(\left(x+y\right)^2\ge0;\left(y-1\right)^2\ge0\)

Mà theo bài ra: \(\left(x+y\right)^2+\left(y-1\right)^2=0\)

\(\Rightarrow\hept{\begin{cases}\left(x+y\right)^2=0\\\left(y-1\right)^2=0\end{cases}}\Rightarrow\hept{\begin{cases}x+y=0\\y-1=0\end{cases}}\Rightarrow\hept{\begin{cases}x+y=0\\y=1\end{cases}}\Rightarrow\hept{\begin{cases}x=-1\\y=1\end{cases}}\)

I write new words in my notebook and then read them aloud

mình ko nhớ rõ cho lắm nhưng chắc là này : I write new words  my notebook and then read them in  aloud

-I write new words in my notebook and then read them aloud.

\(91.\left\{195:\left[84-\left(21+16x\right)\right]\right\}=7\)

\(195:\left[84-\left(21+16x\right)\right]=\frac{7}{91}\)

\(195:\left[84-\left(21+16x\right)\right]=\frac{1}{13}\)

\(84-\left(21+16x\right)=195:\frac{1}{13}\)

\(84-\left(24+16x\right)=195.13\)

\(84-\left(24+16x\right)=2535\)

\(24+16x=84-2535\)

\(24+16x=-2451\)

\(16x=-2451-24\)

\(16x=-2475\)

\(x=\frac{-2475}{16}\)

vay \(x=\frac{-2475}{16}\)

Ta co : \(\left|x+25\right|\ge0\forall x\in Z\)

             \(\left|-y+5\right|\ge0\forall x\in Z\)

Mà : |x + 25| + |-y + 5| = 0 

Nên : \(\hept{\begin{cases}\left|x+25\right|=0\\\left|-y+5\right|=0\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}x+25=0\\-y+5=0\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}x=-25\\y=5\end{cases}}\)

các bạn ơi giúp mình đi mà

a) X=-25; Y=5

bài ni mi ra rồi đk k

khỉ t cz ra

mình cần gấp giúp mình với