{"id":6884,"date":"2021-10-21T21:58:58","date_gmt":"2021-10-21T16:28:58","guid":{"rendered":"https:\/\/mathemerize.com\/?p=6884"},"modified":"2021-10-25T09:49:16","modified_gmt":"2021-10-25T04:19:16","slug":"if-lambda-x2-10xy-12y2-5x-16y-3-0-represents-a-pair-of-straight-lines-then-lambda-is-equal-to","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/if-lambda-x2-10xy-12y2-5x-16y-3-0-represents-a-pair-of-straight-lines-then-lambda-is-equal-to\/","title":{"rendered":"If \\(\\lambda x^2 – 10xy + 12y^2 + 5x – 16y – 3\\) = 0 represents a pair of straight lines, then \\(\\lambda\\) is equal to"},"content":{"rendered":"
Comparing with \\(ax^2+2hxy+by^2+2gx+2fy+c\\) = 0<\/p>\n
Here a = \\(\\lambda\\), b = 12, c = -3, f = -8, g = 5\/2, h = -5<\/p>\n
Using condition \\(abc+2fgh-af^2-bg^2-ch^2\\) = 0, we have<\/p>\n
\\(\\lambda\\)(12)(-3) + 2(-8)(5\/2)(-5) – \\(\\lambda\\)(64) – 12(25\/4) + 3(25) = 0<\/p>\n
\\(\\implies\\)\u00a0 -36\\(\\lambda\\) + 200 – 64\\(\\lambda\\) – 75 + 75 = 0<\/p>\n
\\(\\implies\\)\u00a0 100\\(\\lambda\\) = 200<\/p>\n
\\(\\therefore\\)\u00a0 \\(\\lambda\\) = 2<\/p>\n
If the straight line 3x + 4y + 5 \u2013 k(x + y + 3) = 0 is parallel to y-axis, then the value of k is<\/a><\/p>\n If the line 2x + y = k passes through the point which divides the line segment joining the points (1,1) and (2,4) in the ratio 3:2, then k is equal to<\/a><\/p>\n If x + 4y \u2013 5 = 0 and 4x + ky + 7 = 0 are two perpendicular lines then k is<\/a><\/p>\n Find the equation of lines which passes through the point (3,4) and the sum of intercepts on the axes is 14.<\/a><\/p>\n