Mathbee CBSE Mathbee · CBSE Class 12 Maths
NCERT Class 12 · Ch 3 Miscellaneous Exercise · Q4

NCERT Class 12 Maths · Chapter 3 Matrices · Miscellaneous Exercise Question 4

Find x such that \(\left[\begin{matrix}1 & 2 & 1\end{matrix}\right]\)\(\left[\begin{matrix}1 & 2 & 0\\2 & 0 & 1\\1 & 0 & 2\end{matrix}\right]\)\(\left[\begin{matrix}0\\2\\x\end{matrix}\right]\)=0.

💡 Concept Hints

  1. Check the matrix orders and the meaning of the requested operation before calculating.
  2. Keep row and column indices in order. Compare corresponding entries only after the matrix expressions have compatible dimensions.

✅ Step-by-Step Solution

Final Answer: x=−1.
  1. Multiply the row and matrix first: \(\left[\begin{matrix}6 & 2 & 4\end{matrix}\right]\).
  2. The final row-column product is \(4 \left(x + 1\right)\).
  3. Set 4x+4=0 to get x=−1.

Master Chapter 3: Matrices

Practise interactive questions, flashcards, visual mind maps, and timed board tests for Matrices.
📘 Chapter Notes & All Exercises 🚀 Open Interactive Workspace →
← Previous Question
Find all real x,y,z for A=\(\left[\begin{matrix}0 & 2 y & z\\x & y &…
Next Question →
For A=\(\left[\begin{matrix}3 & 1\\-1 & 2\end{matrix}\right]\)…

All Questions in Matrices — Miscellaneous Exercise

Q1Q2Q3Q4Q5Q6Q7Q8Q9Q10Q11

Related Questions in Matrices

Class 12 Matrices · Mcq Single Correct
Let A be a 2×2 matrix with aᵢⱼ=1 for i≠j and 0 for i=j. Find A².
Class 12 Matrices · Mcq Single Correct
Let A=\(\begin{bmatrix}\cos\alpha & -\sin\alpha\\\sin\alpha & \cos\alpha\end{bmatrix}\)…
Class 12 Matrices · Mcq Single Correct
If \(\begin{bmatrix}2a+b & a−2b\\5c−d & 4c+3d\end{bmatrix}\)=\(\begin{bmatrix}4 & -3\\11 &…
Class 12 Matrices · Mcq Single Correct
How many 3×3 matrices have every entry either 2 or 0?
Class 12 Matrices · Mcq Single Correct
Find x+y for constants x,y such that the identity A⁻¹=xA+yI holds for every real square…
Class 12 Matrices · Mcq Single Correct
If \(\begin{bmatrix}2 & 0\\5 & 4\end{bmatrix}\)=P+Q, where P is symmetric and Q…