Question

    If the points P(–2, 1), Q (α, β) and R (4, –1) are

    collinear and α – β = – 3 then the value of (α + β) is:
    A 2 Correct Answer Incorrect Answer
    B –1 Correct Answer Incorrect Answer
    C 1 Correct Answer Incorrect Answer

    Solution

    Given: Points P(-2,1), Q(α, β), R(4,-1) are collinear. Given: α - β = -3. Find (α + β). Use Collinearity Condition For collinear points, Slope of PQ = Slope of QR Solve for (α + β) We now have:  α - β = -3  α + 3β = 3 Adding both:  2α + 2β = –2  α + β = –1

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