Answers

  • Brainly User
2016-02-01T17:49:34+08:00
Parallel lines have the same slopes.

Change the equation to slope-intercept form, y = mx + b

Equation 1:
   x - y + 1 = 0
   - y = - x - 1
   -1(-y = -x - 1 ) -1
   y = x + 1
   m = 1  

Equation 2:
   2x - ky + 1 = 0
   -ky = -2x - 1
  -ky/-k = -2x/-k  -1/-k
  y = 2x/k + 1/k
  m = 2/k
  
  Solve for k:  
   Equation 2 m = Equation 1 m
   2/k =1
   k = (2)(1)
   k = 2

Substitute:
   2x - ky + 1 = 0
   2x - 2y + 1 = 0
   - 2y = -2x -1
   -2y/-2 = -2x/-2 -1/-2
    y = x + 1/2
    m = 1

Slopes:
   Equation 1:  m = 1
   Equation 2:  m = 1

ANSWER:  k = 2
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