Question

What is the nth term of the arithmetic sequence? 7, 5, 3, 1, …

a. –2n
b. 7 – 2n
c. 9 – 2n
d. n – 2

Answer 1

Hello,

a(1)=7=9-2*1
a(2)=5=9-2*2
a(3)=3=9-2*3
..
a(n)=?=9-2*n

Answer C

Answer 2

an=a1+d(n-1)
an=nth term
a1=first term
d=common difference

7 is first term=a1
the common difference is -2, they increase by -2 each time
an=7-2(n-1)
expand and distribute
an=7-2n+2
an=9-2n

C is answer