a)Ta thấy: \(\left\{\begin{matrix}x^2\ge0\\y^4\ge0\end{matrix}\right.\)\(\Rightarrow x^2+y^4\ge0\)
Mà \(x^2+y^4=0\) suy ra \(\left\{\begin{matrix}x^2=0\\y^4=0\end{matrix}\right.\)\(\Rightarrow\left\{\begin{matrix}x=0\\y=0\end{matrix}\right.\)
b)Ta thấy: \(\left\{\begin{matrix}\left(x-1\right)^2\ge0\\\left(y+2\right)^2\ge0\end{matrix}\right.\)\(\Rightarrow\left(x-1\right)^2+\left(y+2\right)^2\ge0\)
Mà \(\left(x-1\right)^2+\left(y+2\right)^2=0\) suy ra \(\left\{\begin{matrix}\left(x-1\right)^2=0\\\left(y+2\right)^2=0\end{matrix}\right.\)
\(\Rightarrow\left\{\begin{matrix}x-1=0\\y+2=0\end{matrix}\right.\)\(\Rightarrow\left\{\begin{matrix}x=1\\y=-2\end{matrix}\right.\)
c)Ta thấy: \(\left\{\begin{matrix}\left(x-11+y\right)^2\ge0\\\left(x-4-y\right)^2\ge0\end{matrix}\right.\)\(\Rightarrow\left(x-11+y\right)^2+\left(x-4-y\right)^2\ge0\)
Mà \(\left(x-11+y\right)^2+\left(x-4-y\right)^2=0\) suy ra \(\left\{\begin{matrix}\left(x-11+y\right)^2=0\\\left(x-4-y\right)^2=0\end{matrix}\right.\)
\(\Rightarrow\left\{\begin{matrix}x-11+y=0\\x-4-y=0\end{matrix}\right.\)\(\Rightarrow\left\{\begin{matrix}x+y=11\\x-y=4\end{matrix}\right.\)\(\Rightarrow\left\{\begin{matrix}x=\frac{15}{2}\\y=\frac{7}{2}\end{matrix}\right.\)