Post UTME Past Questions Agent
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now

An operation * is defined on the set of real numbers by a * b...

Mathematics
JAMB 2005

An operation * is defined on the set of real numbers by a * b = ab + 2(a + b + 1). find the identity element

  • A. 2
  • B. 1
  • C. -1
  • D. -2
Post UTME Past Questions Agent
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC offline past questions - with all answers and explanations in one app - Download for free
Correct Answer: Option C
Explanation

a * b = ab + 2(a + b + 1)
let e be the identity element
∴ a * e = e * a = a
∴ a * e = a
ae + 2(a + e + 1) = a
ae + 2a + 2e + 2 = a
ae + 2e = a - 2a = 2
(a + 2)e = -a - 2
e = -a-2 / (a+2)
e = -(a+2) / (a+2)
e = -1

There is an explanation video available below.


Report an Error Ask A Question Download App
WAEC offline past questions - with all answers and explanations in one app - Download for free
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Post UTME Past Questions Agent

Explanation Video

WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Post UTME Past Questions Agent

Contributions ({{ comment_count }})

Please wait...

{{ settings.no_comment_msg ? settings.no_comment_msg : 'There are no comments' }}

Quick Questions

Post your Contribution

Please don't post or ask to join a "Group" or "Whatsapp Group" as a comment. It will be deleted. To join or start a group, please click here

{{ quote.posted_by.display_name }}
{{ settings.form_textarea_description }}
 
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Post UTME Past Questions Agent
WAEC offline past questions - with all answers and explanations in one app - Download for free
Post UTME Past Questions Agent
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076
WAEC offline past questions - with all answers and explanations in one app - Download for free
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts