It seems like you're referring to a sequence where "a1" is the first term, "a2" is the second term, and so on. If we assume that the sequence is arithmetic (each term is obtained by adding a fixed number to the previous term), we can find the value of "x" by calculating the common difference between consecutive terms.
Given:
a1 = 5
a2 = x
a3 = 45
In an arithmetic sequence, the common difference (d) can be found using the formula:
d = a2 - a1
Substituting the given values:
d = x - 5
We can also express a3 in terms of a1 and the common difference:
a3 = a1 + 2d
45 = 5 + 2d
Solving for d:
2d = 45 - 5
2d = 40
d = 20
Now that we have the common difference, we can find the value of "x":
x = a1 + d
x = 5 + 20
x = 25
So, in this arithmetic sequence, if a1 = 5 and a3 = 45, then a2 is 25.