To check equality we can try transform info correct form.
First, we can take 12 in front of parenthesis. 12m+12n=12(m+n) We can do this because factor in front of paranthesis mean that all argument from paranthesis are multiplied by this factor. We cant say that 12m+12n is equal to 12mn because we cant multiply [tex]m*n[/tex] here. 12m-12n is not correct too.