Show your work.
(1.7x10^-4)(5x10^-5)
A. 8.5x10^-9
B. 8.5x10^20
C. 6.7x10^-9
D. 6.7x10^20
To multiply two numbers written in scientific notation, you multiply their coefficients (the numbers in front of the 10) and add their exponents. So:
(1.7 x 10^-4) (5 x 10^-5)
= (1.7 x 5) (10^-4 x 10^-5)
= 8.5 x 10^-9
Therefore, the answer is A. 8.5x10^-9.