Answer:
2
Step-by-step explanation:
Ok remember this because its going to appear alot in geometry. Vertical angles are ALWAYS congruent and congruent means when two things are equal/ are the same.
If angle a and b are vertical angles what does that mean?
they are CONGRUENT!
you know A = 20x+ 10 and B= 30x-10
so you can write it as
20x+10 = 30x-10
because Angle A and B equal each other
then get the variable by itself so subtract -20x on both sides
10 = 10x-10
then add 10 to both sides which is
20 = 10x
and divide 10 on both side and 20 divided by 10 is 2
so 2 =x
which is the same as x =2
