Answer:
x=11
Explanation:
The two triangles are congruent, so they have the same side lengths and angles. They are also isosceles triangles, so the opposite angles of the congruent sides are equal. You can use (4x+5) for two base angles due to the two sides being congruent, and the third angle should be (8x-6) since all angles of the two triangles are congruent. Solve the equation for 180, since that is the sum of all three angles in a triangle.
4x+5+4x+5+8x-6=180
16x+4=180
16x=176
x=11