Answer:
x = 50 °
Explanation:
This is an isosceles triangle, and this is apparent because there are two sides which are of the same length (7). This means that the angles opposite to it would also be same (this is one of the properties of an isosceles triangle).
So the other angle would also be x. And the sum of all angles in a triangle would add up to 180.
x + x + 80 = 180
2x = 100
x = 50 °