Question

If the points (a,-1), (2, 1) and (4,5) are collinear. Then, the value of a is

Answer 1

Step-by-step explanation:

If the points are collinear then area of the triangle is 0

1/2[a(1-5)+2(5+1)+4(-1-1)]=0

1/2[-4a+12-8]=0

1/2[-4a+4]=0

-2a+2=0

-2a=-2

a=1

Answer 2

Answer:

When the points are collinear the area of the triangle will be 0

1/2[a(1-5)+2(5+1)+4(-1-1)]=0

1/2[-4a+12-8]=0

1/2[-4a+4]=0

-2a+2=0

-2a=-2

a=1

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