Class 9 Exam  >  Class 9 Questions  >  If x^2 -1 is a factor of ax^3+bx^2+cx+d show ... Start Learning for Free
If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0?
Most Upvoted Answer
If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0?
Proof that a*c = 0 if x^2 - 1 is a factor of ax^3 bx^2 cx d


Let's assume that x^2 - 1 is a factor of ax^3 + bx^2 + cx + d. This means that:



  • x = 1 is a root of the polynomial

  • x = -1 is a root of the polynomial



Using synthetic division


We can use synthetic division to write the polynomial as:



1 0 -a -a-b
1 | a b c d
| a a+b a+c
---------------
a a+b c+d a+b+c


Since x = 1 is a root of the polynomial, the remainder must be 0 when we divide by x - 1. This gives us the equation:


a + (a+b) + (c+d) + (a+b+c) = 0


Simplifying this equation, we get:


3a + 2b + 2c + d = 0


Using x = -1 as well


Similarly, we can use synthetic division to write the polynomial as:



-1 0 -a a-b
-1 | a b c d
| -a a-b -c c-d
----------------
0 b-c -c d-c+d


Since x = -1 is a root of the polynomial, the remainder must be 0 when we divide by x + 1. This gives us the equation:


b - c + d - c + d = 0


Simplifying this equation, we get:


2d - b - 2c = 0


Combining the results


Now we can solve these two equations simultaneously to get a and c in terms of b and d:


3a + 2b + 2c + d = 0


2d - b - 2c = 0


Multiplying the second equation by 3 and adding it to the first equation, we get:


9a + 7b + 4d = 0


Solving for a, we get:


a = -(7b + 4d)/9


Multiplying the second equation by 2 and subtracting it from the first equation, we get:


a + 3b - d = 0


Solving for c, we get:


c = (2d - b)/2


Proof that a*c = 0


Now we can substitute a and c in terms of b and d into the equation ac = 0:


ac = [-(7b + 4
Community Answer
If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0?
Here is your abswer
Attention Class 9 Students!
To make sure you are not studying endlessly, EduRev has designed Class 9 study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Class 9.
Explore Courses for Class 9 exam

Top Courses for Class 9

If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0?
Question Description
If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0? for Class 9 2024 is part of Class 9 preparation. The Question and answers have been prepared according to the Class 9 exam syllabus. Information about If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0? covers all topics & solutions for Class 9 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0?.
Solutions for If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0? in English & in Hindi are available as part of our courses for Class 9. Download more important topics, notes, lectures and mock test series for Class 9 Exam by signing up for free.
Here you can find the meaning of If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0? defined & explained in the simplest way possible. Besides giving the explanation of If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0?, a detailed solution for If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0? has been provided alongside types of If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0? theory, EduRev gives you an ample number of questions to practice If x^2 -1 is a factor of ax^3+bx^2+cx+d show tha a+c=0? tests, examples and also practice Class 9 tests.
Explore Courses for Class 9 exam

Top Courses for Class 9

Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev