Answer: The answer is 1 =n and my work is in the bottom and hope this help :)
Step-by-step explanation:
5n+7=7(n+l)-2n distributive property
5n+7=7n+7-2n Combines Like Term
5n+7= 12n subtract 5n to both side
-5n -5n
7 = 7n divide 7n to both side
7 7
1=n