For scientific notation, multiplication is pretty simple.
In this case, you would only multiply the "regular" number by 2.
(3.7 · 2) · 10^4
= 7.4 · 10^4
However, if it were asking about multiplying the number with something else in scientific notation, in addition to what we did above, you'd add together the exponents.
If you cube the numbers in the left column, you get the numbers in the right column! We can figure this out by understanding that 1^3 = 1, 3^3 = 27, and 6^3 = 216. Then it all falls into place!