Question

What is the value of y?

Answer 1

Since a triangle is 180 degrees in total, you can add the angles you have and subtract 180 by it to get the missing angle, in other words:
79+37+x=180

Answer 2

All angles in a triangle = 180. SO we can make an equation to find y:
79+37+y=180
116+y=180 (combine like terms)
y=64 (subtract the 116)