SOLUTION: Hai sir, please help me on this problem, 3)If the points (-2,1),(a,b) and (4,-1) are collinear and a-b=1. then find the values of a and b.

Algebra ->  Customizable Word Problem Solvers  -> Geometry -> SOLUTION: Hai sir, please help me on this problem, 3)If the points (-2,1),(a,b) and (4,-1) are collinear and a-b=1. then find the values of a and b.      Log On

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Question 398174: Hai sir, please help me on this problem,
3)If the points (-2,1),(a,b) and (4,-1) are collinear and a-b=1. then find the values of a and b.
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

points (-2,1),(a,b) and (4,-1) are collinear

Using the point-slope formula, m+=%28y%5B2%5D+-+y%5B1%5D%29%2F%28x%5B2%5D+-+x%5B1%5D%29

(-2,1 and 

(4,-1)   m =  2/ -6 = -1/3

(-2,1),

(a,b)  m+=+%281-b%29+%2F+%28-2-a%29+=+-1%2F3  |Question states: (a-b) = 1, a = 1+b

(1-b) / (-2-(1+b))     |substituting for a

(1-b)/ (-3 - b) = -1/3 

  -1(-3-b) = 3(1-b)    |cross multiplying

    3 + b = 3 - 3b

        4b = 0

         b = 0  and a = 1    (a = 1+b)

CHECKING our Answer***

(-2,1),

(1,0)  m = 1/-3