\(a,x^2+2x+2=\left(x+1\right)^2+1\ge1>0\)
\(=>bpt:x^2+2x+2\le0\left(vo-li\right)\)
=>bpt vô nghiệm
\(b,4x^2-4x+5=\left(2x-1\right)^2+4\ge4>0\)
\(=>bpt:4x^2-4x+5\le0\left(vo-li\right)\)
=>bpt vô nghiệm
a, \(< =>x^2+2x+1+1\le0\)
\(< =>\left(x+1\right)^2+1\le0\) vô nghiệm với mọi x thuộc R
b, \(< =>\left(2x-1\right)^2+4\le0\)vô nghiệm với mọi x thuộc R
\(a.\)
\(x^2+2x+2=x^2+2x+1+1\)
\(=\left(x+1\right)^2+1\ge1\)
\(b.\)
\(4x^2-4x+5=4x^2-4x+1+4\)
\(=\left(2x-1\right)^2+4\ge4\)
a) \(x^2+2x+2\le0\)
\(\Leftrightarrow x^2+2x+1+1\le0\)
\(\Leftrightarrow\left(x+1\right)^2+1\le0\)(Vô lý)
b) \(4x^2-4x+5\le0\)
\(\Leftrightarrow4x^2-4x+1+4\le0\)
\(\Leftrightarrow\left(2x-1\right)^2+4\le0\)(Vô lý)
a) x2 + 2x + 2 \(\le\) 0
\(\Leftrightarrow\) x2 + 2x + 1 + 1 \(\le\) 0
\(\Leftrightarrow\) ( x + 1 )2 + 1 \(\le\) 0
\(\Leftrightarrow\) ( x + 1 )2 \(\le\) -1 ( vô lí )
\(\Rightarrow\) (đpcm)
b) 4x2 - 4x + 5 ≤ 0
\(\Leftrightarrow\) 4x2 - 4x + 1 + 4 ≤ 0
\(\Leftrightarrow\) ( 2x - 1 )2 + 4 ≤ 0
\(\Leftrightarrow\) ( 2x - 1 )2 ≤ -4 ( vô lí )
\(\Rightarrow\) (đpcm)
