Answer:

Explanation:
To find x, we must first find its corresponding interior angle.
We know that the measures of the interior angles of a triangle add to 180°.
From this, we can construct an equation for x's corresponding interior angle, which I will label y.

Then, we can solve for y by subtracting 55° and 50° from both sides.



Now, we can solve for x, as any interior angle of a triangle and its corresponding exterior angle are supplementary; their measures add to 180°.


