Vertical angles are angles that are opposite each other when the lines cross and they are equal to each other in that they have the same measure.
Keeping that in mind, we get the equation
[tex]50x+10=70x-10[/tex]Let us subtract 50 x from both sides. This gets us
[tex]10=20x-10[/tex]and then let us add 10 to both sides; this gives
[tex]20x=20[/tex]Finally, dividing both sides by 20 gives
[tex]x=1[/tex]which is our answer!
