Solve for n
n\in \left(0,\frac{28}{3}\right)
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3n^{2}-28n<0
Subtract 28n from both sides.
n\left(3n-28\right)<0
Factor out n.
n>0 n-\frac{28}{3}<0
For the product to be negative, n and n-\frac{28}{3} have to be of the opposite signs. Consider the case when n is positive and n-\frac{28}{3} is negative.
n\in \left(0,\frac{28}{3}\right)
The solution satisfying both inequalities is n\in \left(0,\frac{28}{3}\right).
n-\frac{28}{3}>0 n<0
Consider the case when n-\frac{28}{3} is positive and n is negative.
n\in \emptyset
This is false for any n.
n\in \left(0,\frac{28}{3}\right)
The final solution is the union of the obtained solutions.
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