Question

the equation to the pair of straight lines through the origin and perpendicular to 2x²−4xy−7y2=0 is​

Answer 1

We can get equation of pair of line interchanging coefficients of x2 and y2 and changing sign of xy term

Hence required equation is

−3x2+7xy+5y2=0⇒3x2−7xy−5y2=0