Answer:
x=55
Step-by-step explanation:
The exterior angles of a polygon add to 360.
x+x+x+x+x+x+30 = 360
Combine like terms
6x+30 = 360
Subtract 30 from each side
6x+30-30 = 360-30
6x = 330
Divide by 6
6x/6 =330/6
x =55
3(n-7)=-30
3n-21= -30
3n = -9
n= -3
If you are factoring it you can factor it into (x+5)^2