Answer:
21
Step-by-step explanation:

Answer:
a because I dont know why but some one told me it was this
Answer:
x = 44°
Step-by-step explanation:
The sum of the three angles is 180°.
So, x + x + 5 + 2x -1 = 180
4x + 4 = 180
4x = 176
x = 44°
I think that the answe my be b
Answer:
an = a(n-1) - 7
Step-by-step explanation:
the second term is smaller than the first term 7.
a20 = a19 - 7
a19 = a18 - 7
=> a20 = (a18 - 7) - 7
Then you can accumalate until a1
-> a20 = a1 - 19*7 = 86 - 19*7 = -47