29 If a+b--2ab- 0, then the family of straight lines ax+ by c0 is conc

1.	29 If a+b--2ab- 0, then the family of straight lines ax+ by c0 is concurrent atthe pointsomhus RABC lying entirely in first quadrant or fourth quadrant) of area
Answer» if a²+b²-c²-2ab = 0=> a²+b²-2ab = c²=> (a-b)² = c²=> a-b = c => a-c-b = 0, or a-b = -c => a-b+c = 0 so, to make ax+by+c = 0 , look like any of the above results put x = 1 and y = -1 => a(1)+b(-1)+c = 0 => a-b+c = 0✓ so, point is (1,-1) optionB

29 If a+b--2ab- 0, then the family of straight lines ax+ by c0 is concurrent atthe pointsomhus RABC lying entirely in first quadrant or fourth quadrant) of area

Answer»

if a²+b²-c²-2ab = 0=> a²+b²-2ab = c²=> (a-b)² = c²=> a-b = c => a-c-b = 0, or a-b = -c => a-b+c = 0

so, to make ax+by+c = 0 , look like any of the above results

put x = 1 and y = -1 => a(1)+b(-1)+c = 0 => a-b+c = 0✓

so, point is (1,-1)

optionB