`-x^2=-2x+1`
`<=>x^2-2x+1=0`
`<=>(x-1)^2=0`
`<=>x-1=0`
`<=>x=1`
\(-x^2=-2x+1\)
\(\Leftrightarrow-x^2+2x-1=0\)
\(\Leftrightarrow x^2-2x+1=0\)
\(\Leftrightarrow\left(x-1\right)^2=0\)
\(\Leftrightarrow x-1=0\)
\(\Leftrightarrow x=1\)
`-x^2 = -2x+1`
`<=>x^2 = 2x -1`
`<=> x^2 - 2x +1 = 0`
`<=>(x-1)^2 =0`
`<=> x-1=0`
`<=> x = 1`