The sides are all the same length ( an equilateral triangle).
This means each inside angle is 60 degrees ( 180/3 = 60)
Set the equation with x in it equal to 60 and solve for x:
2x - 4 = 60
Add 4 to both sides:
2x = 64
Divide both sides by 2:
x = 32
5.7m questions
7.4m answers