Since, points (x, y), (1.2) and (7,0) are collinear. So area of triangle formed by these points will be zero.
Area of triangle = 1/2[x₁(y₂-y₃)+x₂(y₃-y₁)+x₃(y₁-y₂)]
⇒ Area = 1/2[x(2-0) + 1(0-y)+ 7(y-2)]
⇒ 0 = 1/2[2x-y+7y-14]
⇒ 0 = [2x+6y-14]
⇒ x+3y-7 = 0

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