The three straight lines \( \Large ax+by=c,\ bx+cy=a\ and\ cx+ay=b \) are collinear if:
Correct Answer: A) \( \Large a+b+c = 0 \) |
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Description for Correct answer:
We have \( \Large ax+by=c \) ...(i)
\( \Large bx+cy=a \) ...(ii)
and \( \Large cx+ay=b \) ...(iii)
On adding equation (i), (ii) and (iii), we get
\( \Large ax+by+bx+cy+cx+ay = a+b+c \)
=> \( \Large \left(a+b+c\right)x+ \left(a+b+c\right)y = \left(a+b+c\right) \)
On comparing with \( \Large ox+oy=0 \) (for collinearity)
We get\( \Large a+b+c = 0 \)
Part of solved Straight lines questions and answers :
>> Elementary Mathematics >> Straight lines