Explanation:
it is an equilateral triangle : all 3 sides are if equal length (indicated by the same symbol on each side).
automatically with that comes the conclusion that all 3 angles have the same size.
and since the sum of all angles in a triangle is always 180°, this means every angle is 180/3 = 60°.
therefore,
2x - 4 = 60
2x = 64
x = 32
and FYI
5y = 60
y = 12