3b:
ĐKXĐ: \(x\in R\)
\(\sqrt{x^2+2x+4}+\left(x-1\right)\left(x+3\right)+1=0\)
=>\(\sqrt{x^2+2x+4}+x^2+2x-3+1=0\)
=>\(\sqrt{x^2+2x+4}+x^2+2x-2=0\)
=>\(x^2+2x+4+\sqrt{x^2+2x+4}-6=0\)
=>\(\left(\sqrt{x^2+2x+4}\right)^2+3\sqrt{x^2+2x+4}-2\sqrt{x^2+2x+4}-6=0\)
=>\(\left(\sqrt{x^2+2x+4}+3\right)\left(\sqrt{x^2+2x+4}-2\right)=0\)
=>\(\sqrt{x^2+2x+4}-2=0\)
=>\(\sqrt{x^2+2x+4}=2\)
=>\(x^2+2x+4=4\)
=>\(x^2+2x=0\)
=>x(x+2)=0
=>\(\left[{}\begin{matrix}x=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\left(nhận\right)\\x=-2\left(nhận\right)\end{matrix}\right.\)
Đúng 2
Bình luận (0)
