Mathematics - Complex Number Question with Solution | TestHub

A triangle with vertices represented by $z_1,z_2,z_3$ has opposite sides of lengths in the ratio $2:\sqrt{19}:3$ respectively. Then the value of $4{\left(z_1-z_2\right)}^2+6\left(z_1-z_2\right)\left(z_3-z_2\right)+9{\left(z_3-z_2\right)}^2$ is k. find k.