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A ( - 1 , - 4 ) , B ( b , c ) \text { and } C ( 5 , - 1 ) |
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Answer» If three points (x1, y1), (x2, y2) and (x3, y3) are collinear then [x1(y2- y3) + x2( y3- y1)+ x3(y1- y2)] = 0.A( -1, -4),B(b,c) and C(5, -1) arecollinear then [x1(y2- y3) + x2( y3- y1)+ x3(y1- y2)] = 0.⇒ [ -1( c + 1) +b( -1 + 4) + 5(-4 - c)] = 0.⇒[ - c - 1 -b + 4b - 20 - 5c] = 0.⇒[3b - 6c] = 21⇒b - 2c = 7 -------(1)Given2b + c = 4 -------(2)solving (1) and (2) we getb = 3 and c = -2. |
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