Question 903813
I'm assuming this is an isosceles triangle.


Hint: The three angles are (2x-56), (2x-56), (7x-9) and these three angles add to 180 degrees


(2x-56) + (2x-56) + (7x-9) = 180


This is true for any triangle. We have two copies of (2x-56) because the base angles are congruent in any isosceles triangle.