To multiply numbers in scientific notation, we can multiply the coefficients and add the exponents.
(5 x 10^-7) x (3 x 10^6) = (5 x 3) x (10^-7 x 10^6) = 15 x 10^-1
However, we usually write our answer in scientific notation with the coefficient between 1 and 10, so we can convert this to scientific notation by moving the decimal point one place to the left:
15 x 10^-1 = 1.5 x 10^1
Therefore, the product of (5 x 10^-7) and (3 x 10^6) is 1.5 x 10^1 in scientific notation.