What expression is equal to 12m+12n
a.12mn
b.12m+n
c.12m-12n
d.12(m+n)
explain plz

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  here.
12m-12n is not correct too.

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