Answer:
x=4
Step-by-step explanation:
So basically first we see the angles of this triangle, and we learn that all the angles are congruent. Only a equilateral triangle can have all angles congruent, so this must be equilateral triangle. In equilateral triangles all the sides are congruent. So we just put 5x-12=3x-4. We then solve for x and get 4.
