Hey there mate!
So, when doing this kind of notation (scientific notation), this is pretty much like braking down the number,and trying to make it more simple.

I hope this helps you! :)
Answer:
52d+24433 is the correct answer
I would say 32, just from doing PEMDAS.
Answer:
see explanation
Step-by-step explanation:
Using the double angle identity for sine
sin2x = 2sinxcosx
Consider left side
cos20°cos40°cos80°
=
(2sin20°cos20°)cos40°cos80°
=
(2sin40°cos40°)cos80°
=
(sin80°cos80° )
=
(2sin80°cos80° )
=
. sin160°
=
. sin(180 - 20)°
=
. sin20°
=
= right side , thus proven