Answer:
The missing value of x in this arithmetic sequence is "1"
Step-by-step explanation:
Since this is an arithmetic sequence that means that when we get from one term to the next one we always add/substract the same number each time.
In our case each time we need to find the next term we just add 6 to the current term. For example, after 13 we have 19 which is essentially 13 + 6.
From this we know in order to get from x to 7 we added 6, now know this we can make an equation...
x + 6 = 7
And now we just solve it...
x + 6 = 7
x = 7 - 6
x = 1
