Answer:
well what line do you have a picture??
<h3>

is the simplified expression</h3>
<em><u>Solution:</u></em>
Given that,
We have to simplify

We can simplify the above expression by combining the like terms
Like terms are terms that has same variable with same exponent and same or different coefficient
From given,

Group the like terms

Thus the given expression is simplified
Since the interior is 170 the exteriro must be 10 degrees. There is a total of 360 degrees so 360/10=36 or 36 sides.