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If the points (a₁, b₁), (a₂, b₂) and (a₁ + a₂, b₁ + b₂) are collinear, then

Solution

Correct Option: 3

Three points are given:

(a1,b1)(a₁, b₁), (a2,b2)(a₂, b₂), and (a1+a2,b1+b2)(a₁ + a₂, b₁ + b₂)

These points are collinear, meaning they lie on the same straight line.

For three points to be collinear, the slope between any two pairs of points must be equal.


Finding the slope between (a1,b1)(a₁, b₁) and (a1+a2,b1+b2)(a₁ + a₂, b₁ + b₂):

Slope =(b1+b2)b1(a1+a2)a1= \dfrac{(b₁ + b₂) - b₁}{(a₁ + a₂) - a₁}

Slope =b2a2= \dfrac{b₂}{a₂}


Finding the slope between (a2,b2)(a₂, b₂) and (a1+a2,b1+b2)(a₁ + a₂, b₁ + b₂):

Slope =(b1+b2)b2(a1+a2)a2= \dfrac{(b₁ + b₂) - b₂}{(a₁ + a₂) - a₂}

Slope =b1a1= \dfrac{b₁}{a₁}


Since the points are collinear, the slopes must be equal:

b2a2=b1a1\dfrac{b₂}{a₂} = \dfrac{b₁}{a₁}

Cross-multiplying:

a1b2=a2b1a₁b₂ = a₂b₁

Therefore, the required condition is a1b2=a2b1a₁b₂ = a₂b₁.

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