Hello!
First of all let's multiply our two exponents. When exponents are multiplied, you add them, so -14+28=14. This will leave us with a number multiplied by [tex] 10^{14} [/tex].
Now we multiply 3.4 and 1.8
3.4(1.8)=6.12
Now we combine our two products.
6.12 x 10^14
I hope this helps!