Answer
$2.56 \times 10^{22}$
Work Step by Step
(i) $(ab)^m=a^mb^m$
(ii) $(a^m)^n=a^{mn}$
(iii) $a^{-m} = \dfrac{1}{a^m} a\ne0$
Use the rules above to obtain:
$=6.25^{-2} \times (10^{-12})^{-2}
\\=\dfrac{1}{6.25^2} \times 10^{-12\cdot (-2)}
\\=\dfrac{1}{39.0625} \times 10^{24}
\\=0.0256 \times 10^{24}
\\=(2.56 \cdot 10^{-2}) \times 10^{24}
\\=2.56 \times 10^{-2+24}
\\=2.56 \times 10^{22}$
