can someone please explain how to do this.

• musiclover10045: set the to equal:
  
  x^2 - 4x+4 = 2x-4
   solve for X
  
  subtract 2x from each side:
  x^2 -6x + 4 = -4
  
  subtract 4 from each side:
  
  x^2 -6x = -8
  
  add 8 to both sides:
  
  x^2 -6x +8 = 0
  
  factor the polynomial:
  
  x = 4 and x = 2
  
  using the line equation replace x with 2 and 4 and solve for y
  
  y = 2(2) - 4 = 0
  y = 2(4)-4 = 4
  
  so the 2 points the line  crosses the curve is (2,0) and (4,4)
  
  using those 2 points you can calculate the length:
   distance = sqrt((x2-x1)^2 +(y2-y1)^2
  
  distance = sqrt( (4-2)^2 + (4-0)^2)
  
  distance = sqrt (2^2 + 4^2)
   distance = sqrt (4+16)
  = sqrt 20 
  = 2 sqrt(5)  EXACT LENGTH