Answer:
12
Explanation:
This thing to know about this question is that angle 1 and angle 3 are actually the same.
When two lines intersect, the opposite angles such as that shown in 1 and 3 are equal to each other.
So what you can do is set angle 1 and 3 equal to each other like so:
5x+10 = 70
Then solve for x
5x+10 = 70
5x = 60
x = 12