Answer:

Step-by-step explanation:
By the exterior angle theorem,

Group like terms and solve for x.


Divide both sides by 19;

Answer:
<h3> 10,450</h3>
Step-by-step explanation:
21-13=8 and 29-21=8
So this is aritmetic series where a₁ = 13, and r = 8
Sum of the first n terms:

Answer:

Step-by-step explanation:
Subtract 7 From both sides

7-7 = 0, 16 - 7=9
That leaves 
Hope this helps
~R3V0