Đáp án:
\(\begin{array}{l}
f){\left( {\sqrt 8 - 1} \right)^2}\\
g){\left( {2\sqrt 2 + 1} \right)^2}\\
k){\left( {\sqrt 5 - \sqrt 3 } \right)^2}\\
h){\left( {\sqrt 6 + 1} \right)^2}
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
f)9 - 2\sqrt 8 = 8 - 2\sqrt 8 .1 + 1\\
= {\left( {\sqrt 8 - 1} \right)^2}\\
g)9 + 4\sqrt 2 = 8 + 2.2\sqrt 2 .1 + 1\\
= {\left( {2\sqrt 2 + 1} \right)^2}\\
k)8 - 2\sqrt {15} = 5 - 2.\sqrt 5 .\sqrt 3 + 3\\
= {\left( {\sqrt 5 - \sqrt 3 } \right)^2}\\
h)7 + 2\sqrt 6 = 6 + 2\sqrt 6 .1 + 1\\
= {\left( {\sqrt 6 + 1} \right)^2}
\end{array}\)
