Please show us whatever you did, so we can talk about it.I finished the question I guess without using my 'sneaky move' lol.
Idk how it happened but it was really satisfying!
Since the answer has been given, but without an explanation:I would replace that "blank" on the left by a letter, say "a", and do the square:
\(\displaystyle (a+ 8y^3)^2= a^2+ 16ay^3+ 64y^3\)= ____+ \(\displaystyle 48x^4y^3\)+ _____.
So you want \(\displaystyle 16ay^3= 48x^4y^3\). What must "a" be?