\(x^2-10x=-25\)

\(x^2-10x+25=0\)

\(\left(x-5\right)^2=0\)

\(x-5=0\)

\(x=5\)

\(x^2-10x=-25\)

\(\Leftrightarrow x^2-10x+25=0\)

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

\(\Leftrightarrow x=5\)

\(4x^2+y^2-2y=4x-2\)

\(\Rightarrow4x^2+y^2-2y-4x+2=0\)

\(\Rightarrow\left(4x^2-4x+1\right)+\left(y^2-2y+1\right)=0\)

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

\(\Rightarrow\hept{\begin{cases}2x-1=0\\y-1=0\end{cases}\Rightarrow\hept{\begin{cases}x=\frac{1}{2}\\y=1\end{cases}}}\)

\(P=\left(\frac{x}{\left(x+2\right)\left(x-2\right)}+\frac{1}{x+2}-\frac{2}{x-2}\right):\left(1-\frac{x}{x+2}\right)\)

\(P=\left(\frac{x}{\left(x+2\right)\left(x-2\right)}+\frac{1\cdot\left(x-2\right)}{\left(x+2\right)\left(x-2\right)}-\frac{2\cdot\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}\right):\left(\frac{1\cdot\left(x+2\right)}{x+2}-\frac{x}{x+2}\right)\)

\(P=\frac{x+x-2-2x-4}{\left(x+2\right)\left(x-2\right)}:\frac{x+2-x}{x+2}\)

\(P=\frac{-6}{\left(x+2\right)\left(x-2\right)}:\frac{2}{x+2}\)

\(P=\frac{-6}{\left(x+2\right)\left(x-2\right)}\cdot\frac{x+2}{2}\)

\(P=\frac{-3}{x-2}.\)

Giup mình với. Mình k cho

\(B=\frac{2x-2}{1-3x+3x^2-x^3}=\frac{2\left(x-1\right)}{-\left(x-1\right)^3}=\frac{2}{-\left(x-1\right)^2}< 0\forall x\ne1\)

Biểu thức này không có giá trị nhỏ nhất.

\(\left(x+1\right)\left(x-1\right)-x\left(x+2\right)=3\)

\(\Leftrightarrow x^2-1-x^2-2x=3\)

\(\Leftrightarrow2x=-4\)

\(\Leftrightarrow x=-2\)