Prove that the straight lines joining the origin to the points of intersection of 3x2+5xy-3y2+2x + 3y = 0 and 3x - 2y - 1 = 0 are at right angles.
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Prove that the straight lines joining the origin to the points of intersection of 3x2+5xy-3y2+2x + 3y = 0 and 3x - 2y - 1 = 0 are at right angles.
Given equations are 3x2 + 5xy - 3y2 + 2x + 3y = 0 ..(1)
and 3x - 2y - 1 = 0 \(\Rightarrow\) 3x - 2y = 1
Homogeneous equation (1) with (2) we get,
\(\Rightarrow\) 3x2 + 5xy - 3y2 + 2x + 3y0(1) = 0
\(\Rightarrow\) 3x2 + 5xy - 3y2+ (2x + 3y) (3x - 2y) = 0 [using 2]
\(\Rightarrow\) 3x2 + 5xy - 3y2 + 6x2 - 4xy + 9xy - 6y2 = 0
\(\Rightarrow\) 9x2 + 10xy - 9y2 = 0
Since sum of the co-efficient of x2+Co-efficient of y2 = 9 - 9 = 0.
∴ The lines are at right angles and passing through the origin.
Prove that the straight lines joining the origin to the points of intersection of 3x2+5xy-3y2+2x + 3y = 0 and 3x - 2y - 1 = 0 are at right angles.