if we notice the tickmarks on the sides, that simply means all 3 sides are equal, meaning is an equilateral triangle, and so the interior angles must all be equal and that means each angle is 60°, which means 7x + 4 = 60, and also 8y + 12 = 60.
[tex]\bf 7x+4=60\implies 7x=56\implies x=\cfrac{56}{7}\implies \boxed{x=8} \\\\\\ 8y+12=60\implies 8y=48\implies y=\cfrac{48}{8}\implies \boxed{y=6}[/tex]
