Con điên dở hơi

5x3=15      4x8=32        3x2+7=13

8,32,13 nhé em

okk đg ko

\(\frac{1}{1-x}+\frac{3}{x-1}=0\)( đkxđ : \(x\ne1\))

<=> \(\frac{1\left(x-1\right)}{\left(1-x\right)\left(x-1\right)}+\frac{3\left(1-x\right)}{\left(1-x\right)\left(x-1\right)}=0\)

<=> \(1x-1+3-3x=0\)

<=> \(-2x+2=0\)

<=> \(-2x=-2\)

<=> \(x=1\)( loại vì không tmđk )

Vậy phương trình vô nghiệm 

\(\frac{1}{1-x}+\frac{3}{x-1}=0ĐKXĐ:x\ne\pm1\)

\(\Leftrightarrow\frac{x-1}{\left(1-x\right)\left(x-1\right)}+\frac{3-x}{\left(x-1\right)\left(1-x\right)}=\frac{0}{\left(x-1\right)\left(1-x\right)}\)

Khử mẫu ta đc : \(x-1+3-x=0\)

\(\Leftrightarrow2\ne0\)

Vậy phương trình vô nghiệm 

\(\hept{\begin{cases}3x^2-2y^2-xy+12x-17y-15=0\left(1\right)\\\sqrt{2-x}+\sqrt{6-x-x^2}=y+\sqrt{2y+5}-\sqrt{y+4}\left(2\right)\end{cases}}\)

PT (1) \(\Leftrightarrow3x^2-x\left(y-12\right)-2y^2-17y-15=0\)

\(\Leftrightarrow\Delta=\left(y-12\right)^2+4\cdot3\cdot\left(2y^2+17y+15\right)\)

\(\Leftrightarrow\Delta=y^2-24y+144+24y^2+204y+180\)

\(\Leftrightarrow\Delta=25y^2+180y+324\)

\(\Delta=\left(5y+18\right)^2\)

\(\Leftrightarrow\orbr{\begin{cases}x=\frac{y-12+5y+18}{3}=2y+2\\x=\frac{y-12-5y-18}{3}=\frac{-4y}{3}-10\end{cases}}\)

\(x=2y+2\)

\(\Leftrightarrow\sqrt{2-x}+\sqrt{6-x-x^2}=y+\sqrt{2y+5}-\sqrt{y+4}\)

\(\Leftrightarrow\sqrt{-2y}+\sqrt{6-2y-2-4y^2-8y-4}=y+\sqrt{2y+5}-\sqrt{y+4}\)

\(\Leftrightarrow\sqrt{-2y}+\sqrt{-4y^2-10y+0}=y+\sqrt{2y+5}-\sqrt{y+6}\)

\(\Leftrightarrow y=0\Rightarrow x=2\)

Vậy (x;y)=(2;0)