Question

[Dương tuyết mai]

Tìm  x, y biết :

a) x^2 - 10x + 4y ^2 - 4y +26 = 0

b) 4x^2 - 4/3x + 4 và 1/9 +y^2 - 4y = 0

HELP !!!

Answer 1

[ctk_new]

a) \(x^2-10x+4y^2-4y+26=0\)

\(\Leftrightarrow\left(x^2-10x+25\right)+\left(4y^2-4y+1\right)=0\)

\(\Leftrightarrow\left(x-5\right)^2+\left(2y-1\right)^2=0\)

Mà \(\Leftrightarrow\left(x-5\right)^2+\left(2y-1\right)^2\ge0\)

Dấu "="\(\Leftrightarrow\hept{\begin{cases}x-5=0\\2y-1=0\end{cases}}\Leftrightarrow\hept{\begin{cases}x=5\\y=\frac{1}{2}\end{cases}}\)