If the system of equations 2x + 3y - z = 5,x | vedclass

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

Question

(B) For a system of linear equations to have infinitely many solutions,the determinant of the coefficient matrix must be zero,and the augmented matrix

Vedclass · Accepted Answer

$1120$

Vedclass · Answer

(B) For a system of linear equations to have infinitely many solutions,the determinant of the coefficient matrix must be zero,and the augmented matrix must have a rank less than $3$.The coefficient matrix is $A = \begin{bmatrix} 2 & 3 & -1 \ 1 & \alpha & 3 \ 3 & -1 & \beta \end{bmatrix}$.Setting $|A| = 0$:$2(\alpha\beta + 3) - 3(\beta - 9) - 1(-1 - 3\alpha) = 0$$2\alpha\beta + 6 - 3\beta + 27 + 1 + 3\alpha = 0$$2\alpha\beta + 3\alpha - 3\beta + 34 = 0$  (Equation $1$)Since the system has infinitely many solutions,the planes must be linearly dependent. We can express the third equation as a linear combination of the first two: $L_3 = c_1 L_1 + c_2 L_2$.Comparing coefficients:$2c_1 + c_2 = 3$$3c_1 + c_2\alpha = -1$$-c_1 + 3c_2 = \beta$$5c_1 - 4c_2 = 7$Solving the system of equations for $c_1$ and $c_2$ using the first and last equations:$c_2 = 3 - 2c_1$$5c_1 - 4(3 - 2c_1) = 7 \implies 5c_1 - 12 + 8c_1 = 7 \implies 13c_1 = 19 \implies c_1 = \frac{19}{13}$$c_2 = 3 - 2(\frac{19}{13}) = \frac{39 - 38}{13} = \frac{1}{13}$Substituting $c_1$ and $c_2$ into the other equations:$3(\frac{19}{13}) + \alpha(\frac{1}{13}) = -1 \implies 57 + \alpha = -13 \implies \alpha = -70$$-(\frac{19}{13}) + 3(\frac{1}{13}) = \beta \implies \beta = \frac{-16}{13}$Finally,$13\alpha\beta = 13(-70)(\frac{-16}{13}) = 70 	imes 16 = 1120$.

If the system of equations $2x + 3y - z = 5$,$x + \alpha y + 3z = -4$,and $3x - y + \beta z = 7$ has infinitely many solutions,then $13\alpha\beta$ is equal to

Similar Questions

If the system of equations
$2x + y - z = 5$
$2x - 5y + \lambda z = \mu$
$x + 2y - 5z = 7$
has infinitely many solutions,then $(\lambda + \mu)^2 + (\lambda - \mu)^2$ is equal to

If the system of equations $x + y + z = 6$,$x + 2y + 3z = 10$,and $x + 2y + \lambda z = 0$ has a unique solution,then $\lambda$ is not equal to:

The system of linear equations $\lambda x + 2y + 2z = 5$,$2\lambda x + 3y + 5z = 8$,and $4x + \lambda y + 6z = 10$ has:

The bookshop of a particular school has $10$ dozen chemistry books,$8$ dozen physics books,and $10$ dozen economics books. Their selling prices are Rs. $80$,Rs. $60$,and Rs. $40$ each respectively. Find the total amount the bookshop will receive from selling all the books using matrix algebra.

Let $\lambda, \mu \in R$. If the system of equations
$3x + 5y + \lambda z = 3$
$7x + 11y - 9z = 2$
$97x + 155y - 189z = \mu$
has infinitely many solutions,then $\mu + 2\lambda$ is equal to :

Vedclass Test Series

Exam Paper Generator

Online Exam Module