Welcome to Bytelearn!

Let’s check out your problem:

Which pair of expressions below are equivalent?$\newline$$r+r+r+r+s$ and $5 r s$$\newline$$4(8 r)$ and $12 r$$\newline$$4 r+8 s$ and $8 s+4 r$$\newline$$9 r+9 r$ and $81 r$