Answer:
x = 8
Explanation:
the 3 sides of the triangle are congruent (equal, as indicated by the dashes on the sides )
The triangle is then equilateral with 3 congruent angles , each of 60° so
7x + 4 = 60 ( subtract 4 from both sides )
7x = 56 ( divide both sides by 7 )
x = 8