Question

$3^{-2}$ can be written as

• A. $3{}^2$
• B. $\frac{1}{3^2}$
• C. $\frac{1}{3^{-2}}$
• D. $\frac{-2}{3}$

Answer 1

The correct option is B

$\frac{1}{3^2}$

$3^{-2}$is also written as

By the law of exponent, we know ${\mathrm{a}}^{-\mathrm{n}}=\frac{1}{{\mathrm{a}}^{\mathrm{n}}}$

Therefore, $3^{-2}=\frac{1}{3^2}$

Hence, The correct option is B.