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Question 32 - CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1) - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Last updated at Sept. 4, 2021 by

If A = [8(0 2 3 -4)] and kA = [8(0 3a 2b 24)], then the values of π‘˜,π‘Ž and 𝑏 respectively are:

(a) βˆ’6, βˆ’12, βˆ’18Β  Β  Β  Β  Β  (b) βˆ’6, βˆ’4, βˆ’9

(c) βˆ’6, 4, 9Β  Β  Β  Β  Β  Β  Β  Β  Β  Β (d) βˆ’6, 12, 18

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Transcript

Question 32 If A = [β– 8(0&2@3&βˆ’4)] and kA = [β– 8(0&3π‘Ž@2𝑏&24)], then the values of π‘˜,π‘Ž and 𝑏 respectively are: (a) βˆ’6, βˆ’12, βˆ’18 (b) βˆ’6, βˆ’4, βˆ’9 (c) βˆ’6, 4, 9 (d) βˆ’6, 12, 18 Now, A = [β– 8(0&2@3&βˆ’4)] kA = k [β– 8(0&2@3&βˆ’4)] kA = [β– 8(0 Γ— π‘˜&2 Γ— π‘˜@3 Γ— π‘˜&βˆ’4 Γ— π‘˜)] kA = [β– 8(0&2π‘˜@3π‘˜&βˆ’4π‘˜)] Putting value of kA [β– 8(0&3π‘Ž@2𝑏&24)] = [β– 8(0&2π‘˜@3π‘˜&βˆ’4π‘˜)] Thus, 24 = βˆ’4k βˆ’4k = 24 k = 24/(βˆ’4) k = βˆ’6 Also, 3a = 2k 3a = 2(βˆ’6) 3a = βˆ’12 a = (βˆ’12)/3 a = βˆ’4 So, the correct answer is (B) [β– 8(0&3π‘Ž@2𝑏&24)] = [β– 8(0&2π‘˜@3π‘˜&βˆ’4π‘˜)] Thus, 24 = βˆ’4k βˆ’4k = 24 k = 24/(βˆ’4) k = βˆ’6 Also, 3a = 2k 3a = 2(βˆ’6) 3a = βˆ’12 a = (βˆ’12)/3 a = βˆ’4 2b = 3k 2b = 3(βˆ’6) 2b = βˆ’18 b = (βˆ’18)/2 b = βˆ’9 Thus, k = βˆ’6, a = βˆ’4, b = βˆ’9 So, the correct answer is (B)

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