No products in the cart.

If the third term and the …

CBSE, JEE, NEET, CUET

Question Bank, Mock Tests, Exam Papers

NCERT Solutions, Sample Papers, Notes, Videos

Install Now

If the third term and the 9th term of an ap are 4 and -8 respectively which term of this ap is zero

Posted by Himanshu Raj Singh 6 years, 3 months ago

CBSE > Class 10 > Mathematics

1 answers

Sia ? 6 years, 3 months ago

a(3) = a + 2d
4 = a + 2d
a(9) = a + 8d
-8 = a + 8d
(elimination method)
a + 2d = 4
(-) a + (-)8d =(+) -8 (opposite sign)
0 - 6d = 12
d = -2
a + 2(-2) = 4 (substitution)
a = 8
a(n) = a + (n-1)d
0 = 8 + (n-1)(-2)
= 8 - 2n + 2
= 10 - 2n
2n = 10
n = 5

0Thank You

ANSWER

Test

Related Questions

Prove that root 8 is an irration number

Posted by Sahil Sahil 1 year, 4 months ago

CBSE > Class 10 > Mathematics

2 answers

This content has been hidden. One or more users have flagged this content as inappropriate. Once content is flagged, it is hidden from users and is reviewed by myCBSEguide team against our Community Guidelines. If content is found in violation, the user posting this content will be banned for 30 days from using Homework help section. Suspended users will receive error while adding question or answer. Question comments have also been disabled. Read community guidelines at https://mycbseguide.com/community-guidelines.html

Few rules to keep homework help section safe, clean and informative.

Don't post personal information, mobile numbers and other details.
Don't use this platform for chatting, social networking and making friends. This platform is meant only for asking subject specific and study related questions.
Be nice and polite and avoid rude and abusive language. Avoid inappropriate language and attention, vulgar terms and anything sexually suggestive. Avoid harassment and bullying.
Ask specific question which are clear and concise.

Remember the goal of this website is to share knowledge and learn from each other. Ask questions and help others by answering questions.

Posted by Hari Anand 6 months, 1 week ago

CBSE > Class 10 > Mathematics

0 answers

Venu Gopal has twice

Posted by Lakshay Kumar 1 year, 1 month ago

CBSE > Class 10 > Mathematics

0 answers

X-y=5

Posted by Kishan Thakur 1 month ago

CBSE > Class 10 > Mathematics

1 answers

Don't post personal information, mobile numbers and other details.
Don't use this platform for chatting, social networking and making friends. This platform is meant only for asking subject specific and study related questions.
Be nice and polite and avoid rude and abusive language. Avoid inappropriate language and attention, vulgar terms and anything sexually suggestive. Avoid harassment and bullying.
Ask specific question which are clear and concise.

Remember the goal of this website is to share knowledge and learn from each other. Ask questions and help others by answering questions.

Posted by Kanika . 1 month ago

CBSE > Class 10 > Mathematics