Answer:
9°
Step-by-step explanation:
In a ∆, equal sides make equal angle to the third side. So the angle that's not mentioned is same '2'.
Sum of angles in a ∆ = 180°
80° + m/_2 + m/_2 = 180°
80° + (5x + 5) + (5x + 5) = 180°
10x + 90° = 180°
10x = 90°
x = 9°
