{"id":11137,"date":"2022-06-21T14:38:49","date_gmt":"2022-06-21T09:08:49","guid":{"rendered":"https:\/\/mathemerize.com\/?p=11137"},"modified":"2022-06-21T14:38:50","modified_gmt":"2022-06-21T09:08:50","slug":"for-what-values-of-a-and-b-the-following-system-of-equations-have-infinite-number-of-solutions","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/for-what-values-of-a-and-b-the-following-system-of-equations-have-infinite-number-of-solutions\/","title":{"rendered":"For what values of a and b, the following system of equations have infinite number of solutions ?"},"content":{"rendered":"
(i)<\/strong>\u00a0 For what values of a and b, the following system of equations have infinite number of solutions ?<\/p>\n 2x + 3y = 7<\/p>\n (a – b)x + (a + b)y = 3a + b – 2<\/p>\n (ii)<\/strong>\u00a0 For what value of k will the following pair of linear equations have no solution ?<\/p>\n 3x + y = 1<\/p>\n (2k – 1)x + (k – 1)y = 2k + 1<\/p>\n (i)<\/strong>\u00a0 The given linear equations can be written as<\/p>\n 2x + 3y – 7 = 0<\/p>\n (a – b)x + (a + b)y – (3a + b – 2) = 0<\/p>\n Above equations is of the form<\/p>\n \\(a_1x + b_1y + c_1\\) = 0<\/p>\n \\(a_2x + b_2y + c_2\\) = 0<\/p>\n where,<\/p>\n \\(a_1\\) = 2,\u00a0 \\(b_1\\) = 3,\u00a0 \\(c_1\\) = -7<\/p>\n \\(a_2\\) = (a – b),\u00a0 \\(b_2\\) = (a + b),\u00a0 \\(c_2\\) = -(3a + b – 2)<\/p>\n For the linear equations to have infinitely many solutions,<\/p>\n \\(a_1\\over a_2\\) = \\(b_1\\over b_2\\) = \\(c_1\\over c_2\\)<\/p>\n Here,\u00a0 \\(a_1\\over a_2\\) = \\(2\\over a – b\\),\u00a0 \\(b_1\\over b_2\\) = \\(3\\over a + b\\),\u00a0 \\(c_1\\over c_2\\) = \\(-7\\over -(3a + b – 2)\\) = \\(7\\over 3a + b – 2\\)<\/p>\n \\(\\implies\\)\u00a0 \\(2\\over a – b\\) = \\(3\\over a + b\\) = \\(7\\over 3a + b – 2\\)<\/p>\n \\(\\implies\\)\u00a0 \\(2\\over a – b\\) = \\(3\\over a + b\\)\u00a0 \u00a0and\u00a0 \\(3\\over a + b\\) = \\(7\\over 3a + b – 2\\)<\/p>\n \\(\\implies\\)\u00a0 2a + 2b = 3a – 3b\u00a0 \u00a0and\u00a0 \u00a0 9a + 3b – 6 = 7a + 7b<\/p>\n \\(\\implies\\)\u00a0 2a – 3a = -3b – 2b\u00a0 \u00a0 and\u00a0 \u00a0 \u00a09a – 7a = 7b – 3b + 6<\/p>\n \\(\\implies\\)\u00a0 a = 5b\u00a0 \u00a0……(1)\u00a0 and\u00a0 a = 2b + 3\u00a0 \u00a0 ….(2)<\/p>\n Solving equation (1) and (2), we get<\/p>\n 5b = 2b + 3 \\(\\implies\\)\u00a0 b = 1<\/p>\n Substituting the value of b in equation (1), we get<\/p>\n a = 5<\/p>\n Thus,\u00a0 a = 5 and b = 1.\u00a0<\/strong><\/p>\n (ii)<\/strong>\u00a0 The given linear equations can be written as<\/p>\n 3x + y – 1 = 0<\/p>\n (2k – 1)x + (k – 1)y – (2k + 1) = 0<\/p>\n Above equations is of the form<\/p>\n \\(a_1x + b_1y + c_1\\) = 0<\/p>\n \\(a_2x + b_2y + c_2\\) = 0<\/p>\n where,<\/p>\n \\(a_1\\) = 3,\u00a0 \\(b_1\\) = 1,\u00a0 \\(c_1\\) = -1<\/p>\n \\(a_2\\) = (2k – 1),\u00a0 \\(b_2\\) = (k – 1),\u00a0 \\(c_2\\) = -(2k + 1)<\/p>\n For the linear equations to have no solutions,<\/p>\n \\(a_1\\over a_2\\) = \\(b_1\\over b_2\\) \\(\\ne\\) \\(c_1\\over c_2\\)<\/p>\n \\(\\implies\\)\u00a0 \\(3\\over 2k -1\\) = \\(1\\over k – 1\\)\u00a0 \u00a0and\u00a0 \\(1\\over k – 1\\) \\(\\ne\\)\u00a0 \\(-1\\over -(2k + 1\\)\u00a0 \u00a0 and\u00a0 \\(3\\over 2k -1\\) \\(\\ne\\)\u00a0 \\(1\\over (2k + 1\\)<\/p>\n \\(\\implies\\)\u00a0 3k – 3 = 2k – 1\u00a0 and\u00a0 \u00a02k + 1 \\(\\ne\\)\u00a0 k – 1\u00a0 and\u00a0 6k + 3 \\(\\ne\\)\u00a0 2k – 1<\/p>\n \\(\\implies\\)\u00a0 k = 2\u00a0 \u00a0and\u00a0 \u00a0k\\(\\ne\\)\u00a0 -2\u00a0 \u00a0and\u00a0 k \\(\\ne\\) -1<\/p>\n Hence, the given linear equations has no solutions for k = 2\u00a0 \u00a0and\u00a0 \u00a0k\\(\\ne\\)\u00a0 -2\u00a0 \u00a0and\u00a0 k \\(\\ne\\) -1<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":" Question : (i)\u00a0 For what values of a and b, the following system of equations have infinite number of solutions ? 2x + 3y = 7 (a – b)x + (a + b)y = 3a + b – 2 (ii)\u00a0 For what value of k will the following pair of linear equations have no solution …<\/p>\nSolution :<\/h2>\n