Question

Answer 1

\(5+2.\sqrt{2.x^2+2}=9\)

\(=>2.\sqrt{2.x^2+2}=9-5\)

\(=>2.\sqrt{2.x^2+2}=4\)

\(=>\sqrt{2.x^2+2}=4:2\)

\(=>\sqrt{2.x^2+2}=2\)

\(=>2.x^2+2=4\)

\(=>2.x^2=4-2\)

\(=>2.x^2=2\)

\(=>x^2=2:2\)

\(=>x^2=1\)

\(=>\left[{}\begin{matrix}x^2=1^2\\x^2=\left(-1\right)^2\end{matrix}\right.\)

\(=>\left[{}\begin{matrix}x=1\\x=-1\end{matrix}\right.\)

 

Answer 2

\(\Leftrightarrow2\sqrt{2x^2+2}=4\)

=>\(\sqrt{2x^2+2}=2\)

=>2x^2+2=4

=>2x^2=2

=>x=1 hoặc x=-1

Answer 3

5 + 2 căn(2x² + 2) = 9

2 căn(2x² + 2) = 9 - 5

2 căn(2x² + 2) = 4

căn(2x² + 2) = 2

2x² + 2 = 4

2x² = 4 - 2

2x² = 2

x² = 1

x = 1 hoặc x = -1