What is the 25th term of the arithmetic sequence where a1 = 8 and a9 = 48?

2 Answers
Jul 9, 2018

Answer:

#a_25=128#

Explanation:

We know that ,

#color(blue)(n^(th)term " of the arithmetic sequence is :"#

#color(blue)(a_n=a_1+(n-1)d...to(I)#

We have ,

#color(red)(a_1=8 and a_9=48#

Using #(I)# ,we get

#=>a_9=a_1+(9-1)d=48#

#=>8+8d=48#

#=>8d=48-8=40#

#=>color(red)(d=5#

Again using #(I)# ,we get

#a_25=a_1+(25-1)d#

#=>a_25=8+24(5)#

#=>a_25=128#

Jul 9, 2018

Answer:

#a_(25)=128#

Explanation:

#"the n th term of an arithmetic sequence is"#

#•color(white)(x)a_n=a_1+(n-1)d#

#"where d is the common difference"#

#"given "a_1=8" then"#

#a_9=8+8d=48rArr8d=40rArrd=5#

#a_(25)=8+(24xx5)=128#