Question

4^-2·7^-2 which expressions are equivalent

Answer 1

Recall the following property of exponents:

$a^{-n}=\frac{1}{a^n}$

Then:

$4^{-2}\cdot7^{-2}=\frac{1}{4^2}\cdot\frac{1}{7^2}=\frac{1}{16}\cdot\frac{1}{49}=\frac{1}{784}$