The roots of the equation left| begin{array}{ | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) Given the determinant equation: $\left| \begin{array}{ccc} 1 & 4 & 20 \ 1 & -2 & 5 \ 1 & 2x & 5x^2 \end{array} ight| = 0$ Applying row operati

Vedclass · Accepted Answer

$ -1, 2 $

Vedclass · Answer

(B) Given the determinant equation: $\left| \begin{array}{ccc} 1 & 4 & 20 \ 1 & -2 & 5 \ 1 & 2x & 5x^2 \end{array} ight| = 0$ Applying row operations $R_1 	o R_1 - R_2$ and $R_2 	o R_2 - R_3$: $\left| \begin{array}{ccc} 0 & 6 & 15 \ 0 & -2-2x & 5-5x^2 \ 1 & 2x & 5x^2 \end{array} ight| = 0$ Taking common factors $3$ from $R_1$ and $5$ from $R_2$: $15 \left| \begin{array}{ccc} 0 & 2 & 5 \ 0 & -2(1+x) & 5(1-x)(1+x) \ 1 & 2x & 5x^2 \end{array} ight| = 0$ Taking $(1+x)$ common from $R_2$: $15(1+x) \left| \begin{array}{ccc} 0 & 2 & 5 \ 0 & -2 & 5(1-x) \ 1 & 2x & 5x^2 \end{array} ight| = 0$ Expanding along the first column: $15(1+x) [1(2 	imes 5(1-x) - 5 	imes (-2))] = 0$ $15(1+x) [10-10x + 10] = 0$ $15(1+x) [20-10x] = 0$ $150(1+x)(2-x) = 0$ Thus,$x = -1$ or $x = 2$.

The roots of the equation $\left| \begin{array}{ccc} 1 & 4 & 20 \\ 1 & -2 & 5 \\ 1 & 2x & 5x^2 \end{array} \right| = 0$ are

Similar Questions

The solution set of $\left|\begin{array}{ccc}x & 3 & 5 \\ 2 & 6 & 10 \\ 7 & 21 & 35\end{array}\right|=0$ is . . . . . . .

If $k > 1$ and the determinant of the matrix $A^2$,where $A = \begin{bmatrix} k & k\alpha & \alpha \\ 0 & \alpha & k\alpha \\ 0 & 0 & k \end{bmatrix}$,is $k^2$,then $|\alpha|$ is equal to

If $\left| \begin{array}{ccc} x + 1 & x + 2 & x + 3 \\ x + 2 & x + 3 & x + 4 \\ x + a & x + b & x + c \end{array} \right| = 0$,then $a, b, c$ are in

Evaluate $\left|\begin{array}{ccc}\cos \alpha \cos \beta & \cos \alpha \sin \beta & -\sin \alpha \\ -\sin \beta & \cos \beta & 0 \\ \sin \alpha \cos \beta & \sin \alpha \sin \beta & \cos \alpha\end{array}\right|$

Evaluate the determinant: $\left| {\begin{array}{*{20}{c}}{b + c}& a& a\\b& {c + a}& b\\c& c& {a + b}\end{array}} \right|$

Vedclass Test Series

Exam Paper Generator

Online Exam Module