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If the points a(-1,-4),b(b,c),c(5,-1) are collinear and c=4-2b find the value of b and c |
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Answer» Answer: Given, A(−1,−4),B(b,C)andC(5,−1) Two points are said to be collinear if their SLOPES are equal ⇒ Slope of AB =Slope of BC We have, Slope between two points=( x 2
−x 1
y 2
−y 1
) ⇒ b+1 c+4
= 5−b −1−c
⇒ (c+4)(5−b)=(−1−c)(b+1) As we know, 2b+c=4 ⇒ c=4−2b Substituting this value, we get ⇒ (4−2b+4)(5−b)=(−1−4+2b)(b+1) ⇒ (8−2b)(5−b)=(2b−5)(b+1) ⇒ 40−8b−10b+2b 2 =2b 2 +2b−5b−5 ⇒ 10−18b=−3b−5 ⇒ −18b+3b=−5−40 ⇒ −15b=−45 ⇒ b=3 and c=−2 |
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