Question

If the slope of one of the lines given by $36x^2+2hxy+72y^2=0$ is four times the other, value of $h^2$ is equal to

Answer 1

Let the lines represented by the given equation by
$y=mx$ and $y=4mx$ then $5m=\frac{-2h}{72}$ and $4m^2=\frac{36}{72}$
$\Rightarrow h^2=\frac{25\times (36{)}^2}{8}=4050$