The marks on the line segments tell you they are the same length, and that the triangle is an equilateral triangle. That tells you the angles are the same size, and all are 60°. This lets you find x and y.
(7x+4)° = 60°
7x = 56 . . . . . . . . divide by °, subtract 4
x = 8 . . . . . . . . . . divide by 7
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(8y+12)° = 60°
8y = 48 . . . . . . . . divide by °, subtract 12
y = 6 . . . . . . . . . . divide by 8
