It is only if you are adding or subtracting in Algebra that you need to have like terms.
For multiplication and division you can multiply or divide no matter what the terms or factors are.
rarr " multiply the signs"→ multiply the signs
rarr " muliply the numbers"→ muliply the numbers
rarr " add the indices of variables that are the same"→ add the indices of variables that are the same
2a^2 xx 4a rarr " is the same as " 2xx a xx a xx4 xx a2a2×4a→ is the same as 2×a×a×4×a
=+8a^3+8a3
Note that
(2a)^2 " "and " " 2a^2 (2a)2 and 2a2 are not the same!
(2a)^2 = 4a^2" "(2a)2=4a2 the whole bracket is squared
2a^2 = 2a^2 " "2a2=2a2 only the aa is squared