one angle is 3x-3
another angle is 6(x-10)
Both angles are vertically opposite angles
Vertically opposite angles are always equal
So we equation both the angles and solve for x
3x - 3= 6(x-10)
3x - 3 = 6x - 60
Subtract 6x from both sides
-3x - 3 = -60
Add 3 on both sides
-3x = -57
Divide by 3
x = 19
The value of x= 19