Suppose that $\star(n) = \left\{n - 2, n + 2, 2n, \frac {n}{2}\right\}$. For example, $\star(6) = \{3,4,8,12\}$. For how many distinct integers $n$ does $\star(n)$ have exactly three distinct elements?

Create a real-life situation and create a system and show how it might be modeled algebraically with a system of equations (or inequalities) show all work include a few sentences explaining the situation, your variables of choice and what each represents, and how you would set it up and solve it algebraically. !

What is the perimeter of trapezoid jklm? + units 2 + + units 9 + units 9 + + units

The ratio of the measures of the three angles in a triangle is 2: 9: 4. find the measures of the angels