Any arithmetic sequence can be expressed as:
a(n)=a+d(n-1), a=initial value, d=common difference, n=term number.
The common difference is the constant difference found by subtracting the previous term from any term. In this case:
d=2-1 3/5=1 3/5-1 1/5=-2/5=-0.4 and we can easily see that the first term is 2 so
a(n)=2-0.4(n-1) which can be simplified...
a(n)=2-0.4n+0.4
a(n)=2.4-0.4n, so the 25th term is:
a(25)=2.4-0.4(25)
a(25)= -7.6 or if you prefer...
a(25)= -7 3/5