Answer:
x = 12, y = 4
Explanation:
For the triangles to be congruent by HL , then
x = y + 8 → (1)
4y = x + 4 → (2)
Substitute x = y + 8 into (2)
4y = y + 8 + 4
4y = y + 12 ( subtract y from both sides )
3y = 12 ( divide both sides by 3 )
y = 4
Substitute y = 4 into (1)
x = 4 + 8 = 12