# The sum of first m terms ...

The sum of first m terms of an AP is (4m2-m).If its nth term is 107,find the value of n .Also, find the 21st term of this AP.

Shreya Yadav 6 months, 2 weeks ago

S1=a=3 by putting m=1 in 4m²-m S2=14 by putting m=2 in 4m²-m A2 = S2-S1 A2= 11 AP is 3,11,19...... d= 8 an= a+(n-1)d Now solve for n 107=3+(n-1)8 n=14 21st term = 3+20×8 =163 Hope you will satisfied with my answer☺️☺️

Related Questions:

Subscribe complete study pack and get unlimited access to selected subjects. Effective cost is only ₹ 12.5/- per subject per month. Based on the latest CBSE & NCERT syllabus.

#### CBSE Guide App

Install myCBSEguide mobile app for FREE sample papers, Test Papers, Revision Notes, Previous year question papers, NCERT solutions and MCQ tests

#### CBSE Test Generator

Create papers in minutes

Print with your name & Logo

3 Lakhs+ Questions

Solutions Included

Based on CBSE Blueprint

Best fit for Schools & Tutors

#### Work from Home

• Work from home with us
• Create questions or review them from home

No software required, no contract to sign. Simply apply as teacher, take eligibility test and start working with us. Required desktop or laptop with internet connection

﻿