Actually Welcome to the Concept of the Triangles.
Since there is a linear pair with 40° , the another angle will be 140° ,
also the triangle newly formed is a isosceles one,
hence x = 20°
===> x = 20°
Now apply angle sum property of a triangle on, the other one,
we get as, 70+40+y=180
hence, y = 180-110
y = 70°
Hence angle y ==> 70°