Banner 0
Banner 1
Banner 2
Banner 3
Banner 4
Banner 5
Banner 6
Banner 7
Banner 8
Banner 9

Q.

What should be subtracted from the polynomial 5x4 − 15x3 + 2x2 so that 5x3 − 1 becomes its factor?


see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.
An Intiative by Sri Chaitanya

a

2x2 + x - 3

b

2x2 + x - 2

c

4x2 + x - 3

d

4x2 + x - 2 

answer is A.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

JEE

NEET

NEET

Foundation JEE

Foundation JEE

Foundation NEET

Foundation NEET

CBSE

CBSE

Detailed Solution

We know that if x is a factor of a polynomial p(x), then p(x) is exactly divisible by x.
This means that when p(x) is divided by x, the remainder should be equal to 0.
Now, we know that the division algorithm states that if p(x) and g(x) are two polynomials where g(x) ≠ 0, then there are two polynomials q(x) and r(x) such that p(x) = q(x) × g(x) + r(x). In other words, Dividend = Quotient × Divisor + Remainder.
Rewriting the division algorithm, we get
⇒ p(x) − r(x) = q(x) × g(x) 
p(x)-r(x)g(x) = q(x)
We need to use a long division method to divide  5x4 − 15x3 + 2x2  by  5x3 − 1.
The remainder obtained will be the polynomial/number that should be subtracted from the polynomial 5x4−15x3+2x2 so that 5x3 − 1 becomes its factor.
Now, let us use a long division method to divide   5x4 − 15x3 + 2x2   by   5x3 − 1 .
Therefore, we get
https://www.vedantu.com/question-sets/e9f14ffa-745d-4d16-baa3-849ce35b422f7988041280461724207.png
Therefore, 2x2 + x −3 should be subtracted from 5x4 − 15x3 + 2x2 so that 5x3 − 1 becomes its factor.
We can also verify our answer by subtracting 2x2 + x −3 from 5x4 − 15x3 + 2x2 .
⇒ 5x4 − 15x3 + 2x2 − (2x2 + x −3) = 5x4 − 15x3 + 2x2 − 2x2 − x + 3
⇒ 5x4 − 15x3 + 2x2 − (2x2 + x −3) = 5x4 − 15x3 − x + 3
⇒ 5x4 − 15x3 + 2x2 − (2x2 + x −3) = 5x3 (x − 3) − 1(x − 3)
⇒ 5x4 − 15x3 + 2x2 − (2x2 + x −3) = (5x3 − 1) (x − 3)
Therefore, we can observe that when 2x2 + x −3 is subtracted from 5x4 − 15x3 + 2x2 , 5x3 − 1 becomes a factor of  5x4 − 15x3 + 2x2 .
Hence, option (1) is correct.
 
Watch 3-min video & get full concept clarity
score_test_img

courses

No courses found

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Get Expert Academic Guidance – Connect with a Counselor Today!

best study material, now at your finger tips!

  • promsvg

    live classes

  • promsvg

    progress tracking

  • promsvg

    24x7 mentored guidance

  • promsvg

    study plan analysis

download the app

gplay
mentor

Download the App

gplay
whats app icon
personalised 1:1 online tutoring