Example 16 - Solve system of equations 2x + 5y = 1 3x+2y=7 - Examples part 2 - Example 16 - Examples - Serial order wise - Chapter 4 Class 12 Determinants part 3 - Example 16 - Examples - Serial order wise - Chapter 4 Class 12 Determinants part 4 - Example 16 - Examples - Serial order wise - Chapter 4 Class 12 Determinants

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Transcript

Example 16 Solve the system of equations 2x + 5y = 1 3x + 2y = 7 Step 1 Write equation as AX = B [โ– 8(2&5@3&2)] [โ– 8(๐‘ฅ@๐‘ฆ)] = [โ– 8(1@7)] A = [โ– 8(2&5@3&2)] , X = [โ– 8(๐‘ฅ@๐‘ฆ)] , B = [โ– 8(1@7)] Step 2 Calculate |A|, A = [โ– 8(2&5@3&2)] |A| = |โ– 8(2&5@3&2)| = 2 ร— 2 โ€“ 5 ร— 3 = 4 โ€“ 15 = โ€“ 11 Since |๐‘จ| โ‰  0, System is consistent and the system of equations has a unique solution AX = B X = A-1 B Step 3 Calculating X = A-1 B Here, A-1 = 1/(|A|) adj (A) adj A = [โ– 8(2&5@3&2)] = [โ– 8(2&โˆ’5@โˆ’3&2)] Now, A-1 = 1/(|A|) adj A Putting values = ๐Ÿ/(โˆ’๐Ÿ๐Ÿ) [โ– 8(๐Ÿ&โˆ’๐Ÿ“@โˆ’๐Ÿ‘&๐Ÿ)] & B = [โ– 8(1@7)] Now X = A-1 B [โ– 8(๐‘ฅ@๐‘ฆ)] = (โˆ’1)/11 [โ– 8(2&โˆ’5@โˆ’3&2)] [โ– 8(1@7)] [โ– 8(๐‘ฅ@๐‘ฆ)] = (โˆ’1)/11 [โ– 8(2(1)+(โคถ7โˆ’5)7@โˆ’3(1)+2(7))] [โ– 8(๐‘ฅ@๐‘ฆ)] = (โˆ’1)/11 [โ– 8(2โˆ’35@โˆ’3+14)] = (โˆ’1)/11 [โ– 8(โˆ’33@11)] = [โ– 8(โˆ’33 ร— (โˆ’1)/11@11 ร— (โˆ’1)/11)] [โ– 8(๐‘ฅ@๐‘ฆ)] = [โ– 8(3@โˆ’1)] Hence x = 3 & y = โ€“ 1

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo