Answer:
[tex]x=\boxed{9}[/tex]
Step-by-step explanation:
The measure of each angle in an equilateral triangle is 60°.
(7x -3)° = 60°
7x = 63 . . . . . . . divide by °, add 3
x = 9 . . . . . . . . . .divide by 7
_____
You can tell the triangle is equilateral because all sides are marked with the same mark. That means they are the same length.
