Respuesta :

Answer:

D. 20

Step-by-step explanation:

since the given shape is a parallelogram the parallel sides' length must be equal:

2x-10 = x+30

2x-x = 30+10

x = 40

2y-10 = y+10

2y-y = 10+10

y = 20

since z = x - y

z = 40-20

z = 20