Answer:
8 x 10^5
Explanation:
We can start by grouping the powers of ten together and the other numbers together, as you can move numbers around when multiplying:
4 x 2 x 10^1 x 10^4
4 multiplied by 2 is 8, so we can put that in:
8 x 10^1 x 10^4
Next, using the product rule, 10^1 x 10^4 would be ten to the power of the sum of the two exponents, or 10^(4 + 1), which is 10^5.
We will be left with
8 x 10^5
This is in scientific notation, so no further modification is needed.