This is an equilateral triangle. Measures of angles are equal to 60°. Therefore we have equations
[tex]8y+12=60[/tex] and [tex]7x+4=60[/tex]
[tex]8y+12=60\qquad|-12\\\\8y=48\qquad|:8\\\\\boxed{y=6}\\\\7x+4=69\qquad|-4\\\\7x=56\qquad|:7\\\\\boxed{x=8}[/tex]
