Here, we know, sum of all the angles in a Quadrilateral is 360 & magnitude of opposite angles are equal so:
2(70) + 2(b+60) = 360
2b + 120 = 360 - 140
2b = 220 - 120
b = 100/2
b = 50
Now, angle a & angle b with angle 50 are supplementary, means their sum would be equal to 180, so
a + 110 = 180
a = 180 - 110
a = 70
In short, Your Angles are: a = 70 & b = 50
Hope this helps!