Answer:
x=9
Explanation:
Given is a parallelogram ABCD
AB and CD are parallel sides and also BC with AD
Since AB and CD are parallel we have
angle A + angle D =180
Angle A = 30+5x and angle B =15+10x
Sum = 30+5x+15+10x = 180
Simplify to get
45+15x =180
Subtract 45
15x = 180-45 =135
Divide by 15
x=9