Câu hỏi:

\(\frac{7}{5}.\)

\( - \frac{2}{5}.\)

\(\frac{9}{5}.\)

\(\frac{3}{5}.\)

\({\left( { - x} \right)^1} = - x.\)

\({x^0} = 1{\rm{ }}\left( {x \ne 0} \right)\)

\({x^1} = 1.\)

\({x^{a + 1}} = {x^a}.x\)

Nếu \(a + b = c\) thì \(a = c - b.\)

Nếu \(a + b = c\) thì \(a = c + b.\)

Nếu \(a + b = c\) thì \(a = b - c.\)

Nếu \(a + b = c\) thì \(a = - c - b.\)

\(0,\left( {363} \right).\)

\(0,\left( {36} \right).\)

\(0,\left( 3 \right).\)

\(0,3\left( {63} \right)\)

\(\sqrt {121} .\)

\(0,\left( {12} \right).\)

\(0,010010001...\)

\( - 3,12\left( {345} \right).\)

\(9\) và \( - 9\)

\(\frac{1}{{81}}.\)

\(9.\)

\(\frac{{81}}{2}.\)

Nếu \(x \in \mathbb{Z}\) thì \(x \in \mathbb{R}\)

Nếu \(x \in \mathbb{R}\) thì \(x \in \mathbb{Q}\)

Nếu \(x \in \mathbb{Q}\) thì \(x \in \mathbb{Z}\)

Nếu \(x \in \mathbb{Z}\) thì \(x \in \mathbb{N}.\)

\(\widehat {mEy}.\)

\(\widehat {mEx}.\)

\(\widehat {nEy}.\)

\(\widehat {mEx}\) và \(\widehat {nEy}.\)