Question

find the second, fourth, and eleventh terms of the sequence described by each explicit formula A(n)=2+(n-1)(-2.5)

Answer 1

Given that the explicit formula is given by:
A(n)=2+(n-1)(-2.5)
where n is the number of terms
To get the terms required we simply substitute our values on the expression
the 2nd term will be:
A(2)=2+(2-1)(-2.5)
A(2)=2+1(-2.5)
A(2)=-0.5

the fourth term will be:
A(4)=2+(4-1)(-2.5)
A(4)=2+3(-2.5)
A(4)=2-7.5
A(4)=-5.5

the eleventh term will be:
A(11)=2+(11-1)(-2.5)
A(11)=2+10(-2.5)
A(11)=2-25
A(11)=-23