English

2x + Y − 2z = 4 X − 2y + Z = − 2 5x − 5y + Z = − 2

Advertisements
Advertisements

Question

2x + y − 2z = 4
x − 2y + z = − 2
5x − 5y + z = − 2

Advertisements

Solution

Using the equations we get
\[D = \begin{vmatrix}2 & 1 & - 2 \\ 1 & - 2 & 1 \\ 5 & - 5 & 1\end{vmatrix}\] 
\[ \Rightarrow 2\left( - 2 + 5 \right) - 1\left( 1 - 5 \right) - 2\left( - 5 + 10 \right) = 0\] 
\[ D_1 = \begin{vmatrix}4 & 1 & - 2 \\ - 2 & - 2 & 1 \\ - 2 & - 5 & 1\end{vmatrix}\] 
\[ \Rightarrow 4\left( - 2 + 5 \right) - 1\left( - 2 + 2 \right) - 2\left( 10 - 4 \right) = 0\] 
\[ D_2 = \begin{vmatrix}2 & 4 & - 2 \\ 1 & - 2 & 1 \\ 5 & - 2 & 1\end{vmatrix}\] 
\[ \Rightarrow 2\left( - 2 + 2 \right) - 4\left( 1 - 5 \right) - 2\left( - 2 + 10 \right) = 0\] 
\[ D_3 = \begin{vmatrix}2 & 1 & 4 \\ 1 & - 2 & - 2 \\ 5 & - 5 & - 2\end{vmatrix}\] 
\[ \Rightarrow 2\left( 4 - 10 \right) - 1\left( - 2 + 10 \right) + 4\left( - 5 + 10 \right) = 0\] 
\[\therefore D = D_1 = D_2 = 0\]
Hence, the system of linear equations has infinitely many solutions.

shaalaa.com
  Is there an error in this question or solution?
Chapter 5: Determinants - Exercise 6.4 [Page 85]

APPEARS IN

R.D. Sharma Mathematics Volume 1 and 2 [English] Class 12
Chapter 5 Determinants
Exercise 6.4 | Q 29 | Page 85

RELATED QUESTIONS

Solve the system of linear equations using the matrix method.

2x + y + z = 1

x – 2y – z = `3/2`

3y – 5z = 9


If \[A = \begin{bmatrix}2 & 5 \\ 2 & 1\end{bmatrix} \text{ and } B = \begin{bmatrix}4 & - 3 \\ 2 & 5\end{bmatrix}\] , verify that |AB| = |A| |B|.

 

Without expanding, show that the value of the following determinant is zero:

\[\begin{vmatrix}6 & - 3 & 2 \\ 2 & - 1 & 2 \\ - 10 & 5 & 2\end{vmatrix}\]


Without expanding, show that the value of the following determinant is zero:

\[\begin{vmatrix}a + b & 2a + b & 3a + b \\ 2a + b & 3a + b & 4a + b \\ 4a + b & 5a + b & 6a + b\end{vmatrix}\]


Evaluate :

\[\begin{vmatrix}1 & a & bc \\ 1 & b & ca \\ 1 & c & ab\end{vmatrix}\]


Evaluate the following:

\[\begin{vmatrix}0 & x y^2 & x z^2 \\ x^2 y & 0 & y z^2 \\ x^2 z & z y^2 & 0\end{vmatrix}\]


Prove that:

`[(a, b, c),(a - b, b - c, c - a),(b + c, c + a, a + b)] = a^3 + b^3 + c^3 -3abc`


\[\begin{vmatrix}b + c & a & a \\ b & c + a & b \\ c & c & a + b\end{vmatrix} = 4abc\]


\[\begin{vmatrix}b^2 + c^2 & ab & ac \\ ba & c^2 + a^2 & bc \\ ca & cb & a^2 + b^2\end{vmatrix} = 4 a^2 b^2 c^2\]


Find the area of the triangle with vertice at the point:

 (0, 0), (6, 0) and (4, 3)


Using determinants show that the following points are collinear:

(5, 5), (−5, 1) and (10, 7)


Using determinants show that the following points are collinear:

(1, −1), (2, 1) and (4, 5)


2x − y = 1
7x − 2y = −7


Prove that :

\[\begin{vmatrix}a^2 & a^2 - \left( b - c \right)^2 & bc \\ b^2 & b^2 - \left( c - a \right)^2 & ca \\ c^2 & c^2 - \left( a - b \right)^2 & ab\end{vmatrix} = \left( a - b \right) \left( b - c \right) \left( c - a \right) \left( a + b + c \right) \left( a^2 + b^2 + c^2 \right)\]

Write the value of the determinant \[\begin{vmatrix}2 & - 3 & 5 \\ 4 & - 6 & 10 \\ 6 & - 9 & 15\end{vmatrix} .\]


If |A| = 2, where A is 2 × 2 matrix, find |adj A|.


If \[\begin{vmatrix}2x & 5 \\ 8 & x\end{vmatrix} = \begin{vmatrix}6 & - 2 \\ 7 & 3\end{vmatrix}\] , write the value of x.


The value of \[\begin{vmatrix}5^2 & 5^3 & 5^4 \\ 5^3 & 5^4 & 5^5 \\ 5^4 & 5^5 & 5^6\end{vmatrix}\]

 


The number of distinct real roots of \[\begin{vmatrix}cosec x & \sec x & \sec x \\ \sec x & cosec x & \sec x \\ \sec x & \sec x & cosec x\end{vmatrix} = 0\]  lies in the interval
\[- \frac{\pi}{4} \leq x \leq \frac{\pi}{4}\]


If \[x, y \in \mathbb{R}\], then the determinant 

\[∆ = \begin{vmatrix}\cos x & - \sin x  & 1 \\ \sin x & \cos x & 1 \\ \cos\left( x + y \right) & - \sin\left( x + y \right) & 0\end{vmatrix}\]



Solve the following system of equations by matrix method:
3x + 4y − 5 = 0
x − y + 3 = 0


Solve the following system of equations by matrix method:
 5x + 3y + z = 16
2x + y + 3z = 19
x + 2y + 4z = 25


Solve the following system of equations by matrix method:
3x + 4y + 2z = 8
2y − 3z = 3
x − 2y + 6z = −2


Solve the following system of equations by matrix method:
 x − y + z = 2
2x − y = 0
2y − z = 1


Solve the following system of equations by matrix method:
 8x + 4y + 3z = 18
2x + y +z = 5
x + 2y + z = 5


If A = `[(1, 2, 0), (-2, -1, -2), (0, -1, 1)]`, find A−1. Using A−1, solve the system of linear equations   x − 2y = 10, 2x − y − z = 8, −2y + z = 7.


2x − y + 2z = 0
5x + 3y − z = 0
x + 5y − 5z = 0


Solve the following for x and y: \[\begin{bmatrix}3 & - 4 \\ 9 & 2\end{bmatrix}\binom{x}{y} = \binom{10}{ 2}\]


Write the value of `|(a-b, b- c, c-a),(b-c, c-a, a-b),(c-a, a-b, b-c)|`


If `|(2x, 5),(8, x)| = |(6, -2),(7, 3)|`, then value of x is ______.


If ` abs((1 + "a"^2 "x", (1 + "b"^2)"x", (1 + "c"^2)"x"),((1 + "a"^2) "x", 1 + "b"^2 "x", (1 + "c"^2) "x"), ((1 + "a"^2) "x", (1 + "b"^2) "x", 1 + "c"^2 "x"))`, then f(x) is apolynomial of degree ____________.


If A = `[(1,-1,0),(2,3,4),(0,1,2)]` and B = `[(2,2,-4),(-4,2,-4),(2,-1,5)]`, then:


The system of simultaneous linear equations kx + 2y – z = 1,  (k – 1)y – 2z = 2 and (k + 2)z = 3 have a unique solution if k equals:


If c < 1 and the system of equations x + y – 1 = 0, 2x – y – c = 0 and – bx+ 3by – c = 0 is consistent, then the possible real values of b are


If a, b, c are non-zeros, then the system of equations (α + a)x + αy + αz = 0, αx + (α + b)y + αz = 0, αx+ αy + (α + c)z = 0 has a non-trivial solution if


If the system of linear equations

2x + y – z = 7

x – 3y + 2z = 1

x + 4y + δz = k, where δ, k ∈ R has infinitely many solutions, then δ + k is equal to ______.


If a, b, c are non-zero real numbers and if the system of equations (a – 1)x = y + z, (b – 1)y = z + x, (c – 1)z = x + y, has a non-trivial solution, then ab + bc + ca equals ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×