Answer:
[tex]C(n)=30-20n[/tex]
Step-by-step explanation:
Arithmetic sequence given in the question is,
10, -10, -30, -50........
Explicit formula of an Arithmetic sequence is given by,
[tex]C(n)=C(1)+(n-1)d[/tex]
Here, [tex]C_1=[/tex] First term
[tex]n=[/tex] number of terms
[tex]d=[/tex] common difference
From the given sequence,
[tex]C(1)=10[/tex]
[tex]d=-10-10[/tex]
[tex]=-20[/tex]
Substitute the values in the formula,
[tex]C(n)=10+(n-1)(-20)[/tex]
[tex]C(n)=10-20n+20[/tex]
[tex]C(n)=30-20n[/tex]
