Answer:
x = 6
AD = 24
Explanation:
To find the value of x and AD
We know that the opposite sides of parallelogram are equal
so
AD = BC
3x + 6 = x + 18
3x - x = 18 - 6
2x = 12
x = 12/2
x = 6
now we need to find AD
AD =3x + 6
instead of x we have to put 6
AD = 3 (6) +6
= 18 +6
= 24
AD = 24