Ex 10.1, 8 - Find value of x for which points (x, -1) - Ex 10.1

  1. Chapter 10 Class 11 Straight Lines
  2. Serial order wise

Transcript

Ex10.1, 8 Find the value of x for which the points (x, โ€“1), (2, 1) and (4, 5) are collinear. Let the three points be A (x, โ€“1) , B (2, 1) , C (4, 5) If 3 points are collinear Slope of AB = Slope of BC We know that slope of a line through the points (x1, y1)(x2, y2)is m = (๐‘ฆ2 โˆ’ ๐‘ฆ1)/(๐‘ฅ2 โˆ’ ๐‘ฅ1) 2 = 4 โ€“ 2x 2 โ€“ 4 = -2x -2 = -2x ( โˆ’ 2 )/( โˆ’ 2) = x 1 = x x = 1 Hence value of x is 1

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