Explanation:
college ? I am sure you had to solve such problems latest at high school (if not already at middle school).
remember, the sum of all angles around a single point on one side of a line is 180°. in case of just 2 angles this is called a linear pair of angles or supplementary angles.
therefore,
4x + 2y + 40 = 180
4x + 2y = 140
2x + y = 70
y = 70 - 2x
2x - y + x = 180
3x - y = 180
now we use the first equation in this second equation :
3x - (70 - 2x) = 180
3x - 70 + 2x = 180
5x = 250
x = 50
y = 70 - 2x = 70 - 2×50 = 70 - 100 = -30