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Question 13 - CBSE Class 12 Sample Paper for 2020 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Last updated at Oct. 22, 2019 by

If [1 2 2 1]  [x  y] = [5 4] , then value of y is _______

If [1 2 2 1]  [x  y] = [5 4] , then value of y is __ - Sample Paper

Question 13 - CBSE Class 12 Sample Paper for 2020 Boards - Part 2

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Transcript

Question 13 If [โ– 8(1&2@2&1)][โ– 8(๐‘ฅ@๐‘ฆ)] = [โ– 8(5@4)], then value of y is _______ [โ– 8(1&2@2&1)][โ– 8(๐‘ฅ@๐‘ฆ)] = [โ– 8(5@4)] [โ– 8(1ร—๐‘ฅ+2ร—๐‘ฆ@2ร—๐‘ฅ+1ร—๐‘ฆ)] = [โ– 8(5@4)] [โ– 8(๐‘ฅ+2๐‘ฆ@2๐‘ฅ+๐‘ฆ)] = [โ– 8(5@4)] Therefore, x + 2y = 5 2x + y = 4 Now solving (1) and (2), Doing (2) โ€“ 2 ร— (1) (2x + y) โ€“ 2 ร— (x + 2y) = 4 โ€“ 2 ร— 5 2x + y โ€“ 2x โ€“ 4y = 4 โ€“ 10 y โ€“ 4y = โ€“6 โ€“3y = โ€“6 y = (โˆ’6)/(โˆ’3) y = 2 So, value of y is 2

Class 12
Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.