If ax+ bx + c = 0 and bx+ cx + a = 0 have a common root a ≠ 0 then  equal to

  1. 1
  2. 2
  3. 3
  4. None of these

Answer (Detailed Solution Below)

Option 3 : 3
Free
NDA 01/2025: English Subject Test
30 Qs. 120 Marks 30 Mins

Detailed Solution

Download Solution PDF

Concept:

1. Condition for one and two common roots:

If both roots are common, then the condition is

2. a3 + b3 + c3 - 3abc = (a + b + c)(a2 + b2 + c2 - ab - bc - ca)

If a = b = c, then

a3 + b3 + c3 = 3abc

Calculation:

Given that, 

ax+ bx + c = 0    ----(1)

bx+ cx + a = 0    ----(2)

According to the question, both roots of equations (1) and (2) are common. Therefore, using the concept discussed above

This will be possible only if

⇒ a = b, b = c, c = a

⇒ a3 + b3 + c3 = 3abc

⇒  = 3

Latest NDA Updates

Last updated on Jun 18, 2025

->UPSC has extended the UPSC NDA 2 Registration Date till 20th June 2025.

-> A total of 406 vacancies have been announced for NDA 2 Exam 2025.

->The NDA exam date 2025 has been announced. The written examination will be held on 14th September 2025.

-> The selection process for the NDA exam includes a Written Exam and SSB Interview.

-> Candidates who get successful selection under UPSC NDA will get a salary range between Rs. 15,600 to Rs. 39,100. 

-> Candidates must go through the NDA previous year question paper. Attempting the NDA mock test is also essential. 

Hot Links: teen patti wala game teen patti master old version yono teen patti teen patti vungo