first you multiply both sides by a, so a cancels out on the left side
m+n = ca
subtract m from both sides, so m should cancel out on the left side
n = ca -m
well multiply a with a and cross with out.also times it by c so its m+n=ca right? then you minus m on both sides and he n=cam?
LMFAO idk im only in alg 3 im using common sense.sorry.idk if you were looking for a number answer or to get n by itself or what.hope i helped.goodluck.math sucks.lol