Find the value of k for which of (7, -2), (5, 1), (3, k) are collinear
Find the value of k for which of (7, -2), (5, 1), (3, k) are collinear
A) -4
B) 4
C) -5
D) 5
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Correct option is (B) 4
Given that points (7, -2), (5, 1), (3, k) are collinear.
\(\therefore\) Area of formed triangle is zero.
\(\therefore\frac12|7(1-k)+5(k-(-2))+3(-2-1)|=0\)
\(\Rightarrow|7-7k+5k+10-9|=0\)
\(\Rightarrow|-2k+8|=0\)
\(\Rightarrow-2k+8=0\)
\(\Rightarrow2k=8\)
\(\Rightarrow k=\frac82=4\)
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