Answer:
n = 3 2/7
Explanation:
First of all, look at what you have.
It is a linear equation in n, with several layers of operations performed on it.
You can solve this a couple of ways. (1) Simplify the equation to a 2-step linear equation; (2) Undo the operations done on the variable.
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(1) -5 +18 +21n = 82 . . . eliminate parentheses
21n = 69 . . . . . . . . . . subtract 13
n = 69/21 = 23/7 . . . . divide by the coefficient of n and reduce the fraction
n = 3 2/7
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(2) 3(6 +7n) = 87 . . . . . . add 5
6 +7n = 29 . . . . . . . . . divide by 3
7n = 23 . . . . . . . . . . . . . subtract 6
n = 23/7 . . . . . . . . . . . . divide by the coefficient of n
n = 3 2/7 . . . . write as a mixed number