Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • School
  • provide solution for RD Sharma maths class 12 chapter 5 Determinants exercise Fill in the blanks question 26

provide solution for RD Sharma maths class 12 chapter 5 Determinants exercise  Fill in the blanks question 26

Answers (1)

Answer: 2,7

Hint: Here, we use basic concept of determinant of matrix

Given: x=-y and \left[\begin{array}{lll} x & 3 & 7 \\ 2 & x & 2 \\ 7 & 6 & x \end{array}\right]=0

Solution:

                \left[\begin{array}{lll} x & 3 & 7 \\ 2 & x & 2 \\ 7 & 6 & x \end{array}\right]

                \begin{aligned} &=x\left[\begin{array}{ll} x & 2 \\ 6 & x \end{array}\right]-3\left[\begin{array}{cc} 2 & 2 \\ 7 & x \end{array}\right]+7\left[\begin{array}{cc} 2 & x \\ 7 & 6 \end{array}\right] \\ &=x\left(x^{2}-12\right)-3(2 x-14)+7(12-7 x) \\ &f(x)=x^{3}-12 x-6 x+42+84-49 x=0 \\ &f(x)=x^{3}-67 x+126=0 \end{aligned}

Let put x = 2 and x = 7

                \begin{aligned} &f(2)=(2)^{3}-67(2)+126 \\ &=8-134+126 \\ &=0 \\ &f(7)=(7)^{3}-67(7)+126 \\ &=49 \times 7-67+126 \\ &=0 \end{aligned}

So, 2 and 7 are other roots.

Posted by

infoexpert26

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads

Similar Questions

Trending Articles/News

anam-khan

CBSE extends single girl child scholarship registration deadline till November 20
anam-khan

CBSE reminds schools to submit registration data of Class 9, 11 students by October 16
anam-khan

CBSE reopens online portal for submission of LOC for Class 10, 12 board exams 2026; submit forms by Oct 8

Latest Question