ANSWER
[tex]3.95 \times {10}^{12} [/tex]
EXPLANATION
The first number is
[tex]1.7 \times {10}^{ - 13} [/tex]
The second number is
[tex]3.5 \times {10}^{25} [/tex]
The product of the above two numbers is
[tex]1.7 \times {10}^{ - 13} \times 3.5 \times {10}^{25} [/tex]
We regroup the numbers to obtain,
[tex](1.7 \times 3.5) \times {10}^{ - 13} \times {10}^{25} [/tex]
We now multiply out the expression in the bracket to obtain,
[tex]3.95 \times {10}^{ - 13} \times {10}^{25} [/tex]
Recall also that,
[tex] {a}^{m} \times {a}^{n} = {a}^{m + n}[/tex]
We apply this property to obtain,
[tex]3.95 \times {10}^{ - 13 + 25} [/tex]
This finally simplifies to,
[tex]3.95 \times {10}^{12} [/tex]
Therefore the correct answer is D.
