Answer:
x = 3
Explanation:
We can tell the two pictured angles are equal because they have the red lines showing they are equal. Because of this we can set up the following equation and solve
(for your info, all numbers without x in the steps have °, but for the sake of time left them out)
(equation) 2x + 5 = 7x - 10
(subtracting 2x from both sides & adding 10 to both sides) 15 = 5x
(dividing both sides by 5) 3 = x
Hope this helps, have a nice day :D