L1 and L2 are parallel
so the interior alternate angles are equal
4y - 40 = 3y ( interior alternate angles)
4y - 40 = x + 15 ( vertically opposite angles).
solving the first equation, we get
4y - 3y = 40
y = 40°
putting values of y= 40° in eq. 2, we get
4y - 40= x + 15
4(40) - 40 = x + 15
160 -40 = x + 15
120 - 15 = x
105° = x
X = 105° , Y = 40°