Question

giúp mình với

Answer 1

a: \(x^2-2x+4=x^2-2x+1+3=\left(x-1\right)^2+3>0\)

b: \(-x^2+4x-5\)

\(=-\left(x^2-4x+5\right)\)

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

c: \(=x^2-6x+8+3\)

\(=x^2-6x+9+2\)

\(=\left(x-3\right)^2+2>0\)