Question

Giải:

\(\hept{\begin{cases}3\sqrt{x-2}+2\sqrt{y+1}=7\\5\sqrt{x-2}-3\sqrt{y+1}=-1\end{cases}}\)

Answer 1

Đặt \(\sqrt{x-2}=a;\sqrt{y+1}=b\) nên

\(pt\Leftrightarrow\hept{\begin{cases}3a+2b=7\\5a-3b=-1\end{cases}\Leftrightarrow\hept{\begin{cases}15a+10b=35\\15a-9b=-3\end{cases}}\Leftrightarrow\left(15a+10b\right)-\left(15a-9b\right)=38}\)

\(\Leftrightarrow19b=38\Rightarrow b=2\)\(\Leftrightarrow3a+2.2=7\Rightarrow a=1\)

\(\Rightarrow\hept{\begin{cases}a=\sqrt{x-2}=1\\b=\sqrt{y+1}=2\end{cases}\Leftrightarrow\hept{\begin{cases}x-2=1\\y+1=4\end{cases}\Rightarrow}\hept{\begin{cases}x=3\\y=3\end{cases}}}\)

Vậy \(x=y=3\)

Answer 2

Đặt \(\sqrt{x-2}=a\)và\(\sqrt{y+1}=b\)

Ta có:\(\hept{\begin{cases}3a+2b=7\\5a-3b=-1\end{cases}\Leftrightarrow\hept{\begin{cases}15a+10b=70\\15a-9b=-3\end{cases}}}\)

Lấy trên trừ dươi suy ra 19b=73, thay b vao la tim ra a. Sau do khai can la tim ra x va y

Answer 3

a chep cua dinh duc hung di, ve tren minh nhan nham :((

Answer 4

\(\sqrt{x}=1\)