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In each of the following find the value of 'k', for which the points are collinear. (7,-2), (5, 1), (3, k) |
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Answer» Answer The value of k is 4 Step by step explanation Let us consider A(7,-2) , B (5 ,1) and C(3 , k) Given the points A , B and C are collinear so the gradients of the LINE AB will be equals to the gradient of the line BC Gradient of AB , m₁ =(y₂ - y₁)/(x₂ - x₁) ⇒m₁ = {1 - (-2)}/(5 -7) ⇒m₁= -3/2 ᵃnd the gradient of BC, m₂ = (y₂ - y₁)/(x₂ - x₁) ⇒m₂ =(k - 1)/(3 - 5) ⇒ m₂ = -(k -1)/2 since the gradients of AB and BC are equal so m₁ = m₂ ⇒-3/2 = -(k -1)/2 ⇒-3 = -(k - 1) ⇒3 = k - 1 ⇒k = 4 |
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