answer number 6 for me asap and i will thank u if its correct

Answer:
D
Step-by-step explanation:
The sum of the 3 angles in a triangle = 180°
Sum the 3 given angles and equate to 180, thus
x + 5 + x + 7x - 5 = 180, that is
9x = 180 ( divide both sides by 9 )
x = 20 → D