Question

Simplify the expression. Write the answer using scientific notation.
(5x10^2)^-2

A. 0.04x10^-4
B. -10x10^-4
C. 4.0x10^-6
D. 4.0x10^-5

Answer 1

$(5\cdot10^2)^{-2}=5^{-2}\cdot10^{-4}= \cfrac{1}{5^2} \cdot10^{-4}=\cfrac{1}{25} \cdot10^{-4}=0.04\cdot10^{-4}=4\cdot10^{-6}$

The answer is C. 4.0x10^-6