Pls help with explanation. Will give brainliest

Answer:
E - 40°
Step-by-step explanation:
Angle O = 2 × y
{Angle at center is equal to twice the angle at circumference formed by the same arc}
O = 2 × 70°
O = 140°
x + 90° + 90° + O = 360°
{Sum of angles in a quadrilateral is equal to 360°}
x + 90° + 90° + 140° = 360°
x + 320° = 360°
x = 40°