Answer:
x = 5
y = 40°
Step-by-step explanation:
the median and the base of the large triangle are parallel so angle y has the same measure as the one labeled as 40°
the median is half the base of the large triangle, so 5x = 8x + 10/2
cross-multiply: 10x = 8x + 10
2x = 10
x = 5
