Question

what is \\(\left(-3.1 \times 10^{-7}\
ight)\left(-4.7 \times 10^{-15}\
ight)\\) expressed in scientific notation?\
\\(\bigcirc\\) a. \\(-7.8 \times 10^{-22}\\)\
\\(\bigcirc\\) b. \\(-7.8 \times 10^{8}\\)\
\\(\bigcirc\\) c. \\(1.457 \times 10^{-23}\\)\
\\(\bigcirc\\) d. \\(1.457 \times 10^{-21}\\)

Explanation:

Step1: Multiply the coefficients

$(-3.1) \times (-4.7) = 14.57$

Step2: Multiply the powers of 10

$10^{-7} \times 10^{-15} = 10^{-7 + (-15)} = 10^{-22}$

Step3: Adjust to scientific notation

$14.57 \times 10^{-22} = 1.457 \times 10^{-21}$

Answer:

D. $1.457 \times 10^{-21}$