How do you find the product #(2a-b)^3#?
The solution is:
There may be a more efficient and compact way, and someone may explain it, but I'd tend to just brute-force it. ;-)
Ignore the third bracket for now and do 'FOIL (first, outers, inners, lasts) on the first two brackets:
Collect like terms:
Now multiply each term in the left bracket by each term in the right:
Collect like terms again:
And we're done!