Question 1112334
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<pre>
Your equation is

135 = ({{{((n-2)*180)/n}}}.


and you need solve it for "n".  

For it, multiply both sides by n. You will get


135n = (n-2)*180

135n = 180n - 360

360 = 180n - 135n

360 = 45n

n = {{{360/45}}} = 8.
</pre>

Solved.  &nbsp;&nbsp;The answer is &nbsp;n = 8.