CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1)
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CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1)
Last updated at August 10, 2026 by Teachoo
This question is inspired from Example 5 - Chapter 3 Class 12 - Matrices
![Ques 8 (MCQ) - If [ 2š + š š − 2š 5š − š 4š + 3š ] = [4 −3 11 - CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1)](https://cdn.teachoo.com/b94ec0c1-130e-40a9-95d9-c8970cafa284/slide16.jpg)
Transcript
Question 8 if [ā 8(2š+š&šā2š@5šāš&4š+3š)] = [ā 8(4&ā3@11&24)], then value of a + b ā c + 2d is : (a) 8 (b) 10 (c) 4 (d) ā8 Since matrices are equal. Their corresponding elements are equal 2a + b = 4 5c ā d = 11 a ā 2b = ā 3 4c + 3d = 24 Solving these equations Since matrices are equal. Their corresponding elements are equal 2a + b = 4 5c ā d = 11 a ā 2b = ā 3 4c + 3d = 24 Solving these equations Solving (1) 2a + b = 4 b = 4 ā 2a Putting value of b in (3) a ā 2b = ā 3 Putting b = 4 ā 2a a ā 2(4 ā 2a) = -3 a ā 8 + 4a = -3 a + 4a = -3 + 8 5a = 5 a = 5/5 a = 1 From (1) 2a + b = 4 Putting a = 1 2(1) + b = 4 2 + b = 4 b = 4 ā 2 b = 2 From (2) 5c ā d = 11 5c = 11 + d 5c ā 11 = d d = 5c ā 11 Solving (4) 4c + 3d = 24 Putting d = 5c ā 11 4c + 3(5c ā 11) = 24 4c + 15c ā 33 = 24 19c ā 33 = 24 19c = 24 + 33 19c = 57 c = 57/19 c = 3 Now, d = 5c ā 11 Putting c = 3 d = 5(3) ā 11 d = 15 ā 11 d = 4 Hence, a = 1, b = 2, c = 3 and d = 4 Thus, a + b ā c + 2d = 1 + 2 ā 3 + 2(4) = 8 So, the correct answer is (a)
