When you have a number next to a letter it's the same as multiplying them so, 3m=18 is the same as 3 x m = 18.
You have to get you letter by itself. To do this divide each side by 3. That you will give you M=6 as your answer.
3m=18
3m/3 = 18/3
m=6 check your answer 3x6=18
3m = 18
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