If 3x2 + ax + 4 is perfectly divisible by x – 5, then the value of a is:

This question was previously asked in
RRB ALP Previous Paper 2 (Held On: 9 Aug 2018 Shift 2)
View all RRB ALP Papers >
  1. -12
  2. -5
  3. -15.8
  4. -15.6

Answer (Detailed Solution Below)

Option 3 : -15.8
Free
General Science for All Railway Exams Mock Test
2.1 Lakh Users
20 Questions 20 Marks 15 Mins

Detailed Solution

Download Solution PDF

Given our polynomial is (3x2 + ax + 4) and it is perfectly divisible by (x - 5), the remainder is (0) when (x = 5).

So, let's substitute (x = 5) into (3x2 + ax + 4) and set it equal to (0):

[3(5)2 + a(5) + 4 = 0]

[3(25) + 5a + 4 = 0]

[75 + 5a + 4 = 0]

[79 + 5a = 0]

Solving for (a), we get:

[5a = -79]

[a = -79/5

[a = -15.8]

∴ The value of (a) is (-15.8).

Alternate Method3x2 + ax + 4 is perfectly divisible by x – 5,

⇒ 3 × 25 + 5a + 4 = 0

⇒ 5a = -79

∴ a = -15.8
Latest RRB ALP Updates

Last updated on Jun 2, 2025

-> The RRB NTPC Admit Card 2025 has been released on 1st June 2025 on the official website.

-> Railway Recruitment Board activated the RRB ALP application form 2025 correction link, candidates can make the correction in the application form till 31st May 2025. 

-> The Railway Recruitment Board (RRB) has released the official RRB ALP Notification 2025 to fill 9,970 Assistant Loco Pilot posts.

-> The Railway Recruitment Board (RRB) has released the official RRB ALP Notification 2025 to fill 9,970 Assistant Loco Pilot posts.

-> The official RRB ALP Recruitment 2025 provides an overview of the vacancy, exam date, selection process, eligibility criteria and many more.

->The candidates must have passed 10th with ITI or Diploma to be eligible for this post. 

->The RRB Assistant Loco Pilot selection process comprises CBT I, CBT II, Computer Based Aptitude Test (CBAT), Document Verification, and Medical Examination.

-> This year, lakhs of aspiring candidates will take part in the recruitment process for this opportunity in Indian Railways. 

-> Serious aspirants should prepare for the exam with RRB ALP Previous Year Papers.

-> Attempt RRB ALP GK & Reasoning Free Mock Tests and RRB ALP Current Affairs Free Mock Tests here

Get Free Access Now
Hot Links: teen patti go teen patti gold download teen patti master purana teen patti gold apk download teen patti joy 51 bonus