Question 251062
You will have a better chance of a response if you input one problem as a time.
Otherwise they are too time consuming and we also might get the idea we are doing your homework for you.
The first problem is easy but time consuming to explain so I will tackle the second one for you
(s + t) * (s^2 - st + t^2)
 multiply (s^2 - st + t^2) by s and then by t and add them
s*(s^2 - st + t^2)+t*(s^2 - st + t^2)
Do basically the same thing with the third problem
4d*(81d^2/4d^2 - 32d + 64)-16/9d*(81d^2/4d^2 - 32d + 64))
Pay attention to signs-- plus and minus
Resubmit the first one on its own.