Multiply. Write your answer in scientific notation. 7 · (4 × 10⁹)

To solve the problem (7 cdot (4 times 10^9)), we can follow these steps:

1. Multiply the coefficients: First, multiply 7 by 4.
[

7 cdot 4 = 28

]

2. Combine with (10^9): Now, since we are working with scientific notation, we keep (10^9) as it is.

[

28 times 10^9

]

3. Convert to proper scientific notation: In scientific notation, we need a coefficient between 1 and 10. So, we rewrite 28 as (2.8 times 10^1):

[

28 times 10^9 = (2.8 times 10^1) times 10^9

]

4. Use the product of powers rule: We can add the exponents of 10:

[

2.8 times 10^{1+9} = 2.8 times 10^{10}

]

So, the final answer in scientific notation is:

[

boxed{2.8 times 10^{10}}

]

If you have any additional questions or need further help, feel free to ask!